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/utils/is-defined.ts

@@ -0,0 +1,3 @@
+export const isDefined = <T>(value: T | null | undefined): value is T => {
+  return value !== null && value !== undefined;
+};