Database Manager

done:
+ master.sql as resource
+ implemented incremental database changes also for Master
+ dbUp sql script variables implemented
+ improved database handling and creation code
+ simpified database creation
+ almost all Database and Tenant creation moved to DatabaseManager.cs (rest code marked with TODO)
+ Unattended install of master can be performed by settings in appsettings.json
+ Improved IsInstalled checking
+ Removed DBSchema field from Tenant
+ Default database and site creation moved to Program.Main

Oqtane.Client/Services/Interfaces/IInstallationService.cs

@@ -1,12 +1,13 @@
 using Oqtane.Models;
 using System.Threading.Tasks;
+using Oqtane.Shared;
 
 namespace Oqtane.Services
 {
     public interface IInstallationService
     {
         Task<Installation> IsInstalled();
-        Task<Installation> Install(string connectionstring);
+        Task<Installation> Install(InstallConfig config);
         Task<Installation> Upgrade();
     }
 }