Implements MediaService for U4-941

Minor update to the ContentType/MediaType repositories to insure that CT references are removed when deleting.
Updates Media- and ContentMappers to map ContentTypeId.
Updates Media to have internal Trash-method.

src/Umbraco.Core/Models/Rdbms/ContentDto.cs

@@ -18,7 +18,7 @@ namespace Umbraco.Core.Models.Rdbms
         public int NodeId { get; set; }
 
         [Column("contentType")]
-        public int ContentType { get; set; }
+        public int ContentTypeId { get; set; }
 
         [ResultColumn]
         public NodeDto NodeDto { get; set; }

src/Umbraco.Core/Models/Rdbms/ContentType2ContentTypeDto.cs

@@ -8,7 +8,7 @@ namespace Umbraco.Core.Models.Rdbms
     internal class ContentType2ContentTypeDto
     {
         [Column("parentContentTypeId")]
-        [PrimaryKeyColumn(AutoIncrement = false, Clustered = true, Name = "PK_cmsContentType2ContentType", OnColumns = "[parentContentTypeId], [childContentTypeId]")]
+        [PrimaryKeyColumn(AutoIncrement = false, Clustered = true, Name = "PK_cmsContentType2ContentType", OnColumns = "parentContentTypeId, childContentTypeId")]
         public int ParentId { get; set; }
 
         [Column("childContentTypeId")]