feat: drop calendar repository (#5824)

This PR is replacing and removing all the raw queries and repositories
with the new `TwentyORM` and injection system using
`@InjectWorkspaceRepository`.
Some logic that was contained inside repositories has been moved to the
services.
In this PR we're only replacing repositories for calendar feature.

---------

Co-authored-by: Weiko <corentin@twenty.com>
Co-authored-by: bosiraphael <raphael.bosi@gmail.com>
Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-server/src/engine/twenty-orm/custom.workspace-entity.ts

@@ -36,7 +36,7 @@ export class CustomWorkspaceEntity extends BaseWorkspaceEntity {
   })
   @WorkspaceIsNullable()
   @WorkspaceIsSystem()
-  position: number;
+  position: number | null;
 
   @WorkspaceRelation({
     standardId: CUSTOM_OBJECT_STANDARD_FIELD_IDS.activityTargets,