Update DbTriggerParams and EF Core package versions

- Changed DbTriggerParams to use ICollection<string> for flexibility.
- Updated Microsoft.EntityFrameworkCore.SqlServer to version 9.0.6.
- Made _logger in EGDbContext nullable and optional in constructor.
- Updated logging statements to prevent null reference exceptions.
- Added Microsoft.EntityFrameworkCore.SqlServer package for net8.0 and net9.0.
- Introduced appsettings.migration.json for connection strings and trigger parameters.
- Added EGDbContextFactory for design-time DbContext creation.

EnvelopeGenerator.Application/Configurations/DbTriggerParams.cs

@@ -3,6 +3,6 @@
 /// <summary>
 /// 
 /// </summary>
-public class DbTriggerParams : Dictionary<string, IEnumerable<string>>
+public class DbTriggerParams : Dictionary<string, ICollection<string>>
 {
 }