feat: manually implement joinColumn (#6022)

This PR introduce a new decorator named `@WorkspaceJoinColumn`, the goal
of this one is to manually declare the join columns inside the workspace
entities, so we don't have to rely on `ObjectRecord` type.

This decorator can be used that way:

```typescript
  @WorkspaceRelation({
    standardId: ACTIVITY_TARGET_STANDARD_FIELD_IDS.company,
    type: RelationMetadataType.MANY_TO_ONE,
    label: 'Company',
    description: 'ActivityTarget company',
    icon: 'IconBuildingSkyscraper',
    inverseSideTarget: () => CompanyWorkspaceEntity,
    inverseSideFieldKey: 'activityTargets',
  })
  @WorkspaceIsNullable()
  company: Relation<CompanyWorkspaceEntity> | null;

  // The argument is the name of the relation above
  @WorkspaceJoinColumn('company')
  companyId: string | null;
```

packages/twenty-server/src/engine/core-modules/calendar/timeline-calendar-event.service.ts

@@ -31,9 +31,7 @@ export class TimelineCalendarEventService {
     const calendarEventIds = await this.calendarEventRepository.find({
       where: {
         calendarEventParticipants: {
-          person: {
-            id: Any(personIds),
-          },
+          personId: Any(personIds),
         },
       },
       select: {
@@ -81,8 +79,8 @@ export class TimelineCalendarEventService {
       const participants = event.calendarEventParticipants.map(
         (participant) => ({
           calendarEventId: event.id,
-          personId: participant.person?.id ?? null,
-          workspaceMemberId: participant.workspaceMember?.id ?? null,
+          personId: participant.personId ?? null,
+          workspaceMemberId: participant.workspaceMemberId ?? null,
           firstName:
             participant.person?.name?.firstName ||
             participant.workspaceMember?.name.firstName ||
@@ -135,9 +133,7 @@ export class TimelineCalendarEventService {
   ): Promise<TimelineCalendarEventsWithTotal> {
     const personIds = await this.personRepository.find({
       where: {
-        company: {
-          id: companyId,
-        },
+        companyId,
       },
       select: {
         id: true,