consolidate Service interface and implementation classes

Oqtane.Client/Services/InstallationService.cs

@@ -10,6 +10,38 @@ using System.Linq;
 
 namespace Oqtane.Services
 {
+    /// <summary>
+    /// Service to manage (install master database / upgrade version / etc.) the installation
+    /// </summary>
+    public interface IInstallationService
+    {
+        /// <summary>
+        /// Returns a status/message object with the current installation state 
+        /// </summary>
+        /// <returns></returns>
+        Task<Installation> IsInstalled();
+
+        /// <summary>
+        /// Starts the installation process 
+        /// </summary>
+        /// <param name="config">connectionString, database type, alias etc.</param>
+        /// <returns>internal status/message object</returns>
+        Task<Installation> Install(InstallConfig config);
+
+        /// <summary>
+        /// Starts the upgrade process
+        /// </summary>
+        /// <param name="backup">indicates if files should be backed up during upgrade</param>
+        /// <returns>internal status/message object</returns>
+        Task<Installation> Upgrade(bool backup);
+
+        /// <summary>
+        /// Restarts the installation
+        /// </summary>
+        /// <returns>internal status/message object</returns>
+        Task RestartAsync();
+    }
+
     [PrivateApi("Don't show in the documentation, as everything should use the Interface")]
     public class InstallationService : ServiceBase, IInstallationService
     {