Make synchronization works from FileEvent and ObserverService

Description

File's event trigger File synchronization for CLOSE_WRITE (= creation & modification) and DELETE event.

it also include some fix about ObserverService's binding to SynchronizationService.

Database structure has been updated

I cherry-picked each commit of !83 (closed) to get a clean MR Without commit from older outdated branch.

Issue(s)

closes https://gitlab.e.foundation/e/os/backlog/-/issues/4

Check list

• Self review
• Test procedure explained
• Tested on fresh install
• Tested applied as an update
• License