feat: Implement ExistingDatabaseContext for managing existing databases with customizable naming strategies and auto-discovery of entities

feat: Add SqlServerSchemaProvider for extracting database schema information from SQL Server

feat: Introduce DatabaseType and NamingStrategy enums for better database management and naming conventions

feat: Create IDatabaseDiscovery and IDatabaseManager interfaces for database operations and metadata retrieval

feat: Develop REST service client architecture with BaseRestServiceClient and SAP Business One specific implementation

feat: Implement REST service discovery page with UI for connecting to SAP Business One Service Layer and displaying discovered entities

DataConnection/DB/Interfaces/IDatabaseDiscovery.cs

@@ -0,0 +1,62 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+namespace DataConnection.Interfaces;
+
+/// <summary>
+/// Interfaccia per la scoperta dei database disponibili sul server
+/// </summary>
+public interface IDatabaseDiscovery
+{
+    /// <summary>
+    /// Ottiene l'elenco di tutti i database disponibili sul server
+    /// </summary>
+    /// <param name="serverConnectionString">Stringa di connessione al server (senza specificare il database)</param>
+    /// <param name="excludeSystemDatabases">Se true, esclude i database di sistema</param>
+    /// <returns>Lista di nomi dei database disponibili</returns>
+    Task<List<string>> GetAvailableDatabasesAsync(string serverConnectionString, bool excludeSystemDatabases = true);
+    
+    /// <summary>
+    /// Ottiene informazioni dettagliate sui database disponibili
+    /// </summary>
+    /// <param name="serverConnectionString">Stringa di connessione al server</param>
+    /// <param name="excludeSystemDatabases">Se true, esclude i database di sistema</param>
+    /// <returns>Dizionario con nome database e metadati</returns>
+    Task<Dictionary<string, DatabaseInfo>> GetDatabasesInfoAsync(string serverConnectionString, bool excludeSystemDatabases = true);
+}
+
+/// <summary>
+/// Informazioni sul database
+/// </summary>
+public class DatabaseInfo
+{
+    /// <summary>
+    /// Nome del database
+    /// </summary>
+    public string Name { get; set; }
+    
+    /// <summary>
+    /// Dimensione del database in MB
+    /// </summary>
+    public double SizeMB { get; set; }
+    
+    /// <summary>
+    /// Data di creazione
+    /// </summary>
+    public System.DateTime CreationDate { get; set; }
+    
+    /// <summary>
+    /// Stato del database (online, offline, ecc.)
+    /// </summary>
+    public string Status { get; set; }
+    
+    /// <summary>
+    /// Proprietario del database
+    /// </summary>
+    public string Owner { get; set; }
+    
+    /// <summary>
+    /// Indica se è un database di sistema
+    /// </summary>
+    public bool IsSystemDatabase { get; set; }
+}

DataConnection/DB/Interfaces/IDatabaseManager.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+using System.Threading.Tasks;
+
+namespace DataConnection.Interfaces;
+
+/// <summary>
+/// Interfaccia per la gestione di database preesistenti tramite EF Core
+/// </summary>
+public interface IDatabaseManager : IDisposable
+{
+    /// <summary>
+    /// Verifica la connessione al database
+    /// </summary>
+    Task<bool> TestConnectionAsync();
+    
+    /// <summary>
+    /// Ottiene entità dal database in base ai criteri specificati
+    /// </summary>
+    /// <typeparam name="T">Tipo di entità</typeparam>
+    /// <param name="filter">Espressione di filtro</param>
+    /// <param name="orderBy">Espressione di ordinamento</param>
+    /// <param name="includeProperties">Proprietà di navigazione da includere</param>
+    /// <param name="skip">Numero di elementi da saltare</param>
+    /// <param name="take">Numero di elementi da prendere</param>
+    Task<IEnumerable<T>> GetAsync<T>(
+        Expression<Func<T, bool>> filter = null,
+        Func<IQueryable<T>, IOrderedQueryable<T>> orderBy = null,
+        string includeProperties = "",
+        int? skip = null,
+        int? take = null) where T : class;
+    
+    /// <summary>
+    /// Ottiene un'entità singola in base alla chiave primaria
+    /// </summary>
+    Task<T> GetByIdAsync<T>(object id) where T : class;
+    
+    /// <summary>
+    /// Esegue una query SQL raw
+    /// </summary>
+    Task<IEnumerable<T>> ExecuteQueryAsync<T>(string sql, params object[] parameters) where T : class;
+    
+    /// <summary>
+    /// Esegue un comando SQL che non restituisce risultati
+    /// </summary>
+    Task<int> ExecuteCommandAsync(string sql, params object[] parameters);
+    
+    /// <summary>
+    /// Ottiene i metadati delle tabelle nel database
+    /// </summary>
+    Task<IDictionary<string, IEnumerable<DbColumnInfo>>> GetDatabaseSchemaAsync();
+}
+
+/// <summary>
+/// Informazioni su una colonna del database
+/// </summary>
+public class DbColumnInfo
+{
+    public string Name { get; set; }
+    public string DataType { get; set; }
+    public bool IsNullable { get; set; }
+    public bool IsPrimaryKey { get; set; }
+    public bool IsForeignKey { get; set; }
+    public string ReferencedTable { get; set; }
+    public string ReferencedColumn { get; set; }
+}

DataConnection/DB/Interfaces/IDatabaseSchemaProvider.cs

@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+namespace DataConnection.Interfaces;
+
+/// <summary>
+/// Interfaccia per provider di estrazione dello schema del database
+/// </summary>
+public interface IDatabaseSchemaProvider
+{
+    /// <summary>
+    /// Estrae lo schema del database (tabelle e colonne)
+    /// </summary>
+    /// <param name="connectionString">Stringa di connessione al database</param>
+    /// <returns>Struttura gerarchica delle tabelle e delle loro colonne</returns>
+    Task<IDictionary<string, IEnumerable<DbColumnInfo>>> GetDatabaseSchemaAsync(string connectionString);
+}