We've seen a few cascading errors (e.g. comment.activityId would be non
nullable but cascade behavior is set to "set null"). I think it's safer
if we have to explicitly chose the deletion behavior it every time.
Especially since Postgres default to "No action" while we defaulted to
"Set Null", which is confusing.
In the future we will most likely introduce a second param
`onSoftDelete` in the decorator
## Context
SyncExternalId should be renamed because this won't always represent an
id. For example, microsoft API does not use ids but dates for their
sync. Also we think external is a bit redundant so we are removing it.
Note: this field is not used by the front-end (and will probably never
be)
- If sync fails we set authFailedAt
- This information is displayed in the frontend in accounts with a `Sync
Failed` pill
- The user can reconnect his account in the dropdown menu
- A new OAuth flow is triggered
- The account is synced
* update calendarEvent labels and description to match Figma
* modify conferenceUri to conferenceLink with LINK type
* update format-google-calendar-event.util to match new conferenceLink
* update CalendarEventDetails since overriding the fields is no longer needed
* fix mock metadata
* generate new uuid for field conferenceLink
* feat: wip refactor default-value
* feat: health check to migrate default value
* fix: tests
* fix: refactor defaultValue to make it more clean
* fix: unit tests
* fix: front-end default value
