LT-14377, forbid share my projects with wrong ProjectsFolder

1. Share my projects cannot be turned on unless ProjectsFolder as seen
by this user is the same as the one (based on HKLM) seen by the
FwRemoteDatabaseConnectorService.

2. Even if it is turned on, this doesn't take effect if the folders
are different. This allows a different user with a personal projects
folder to keep working.

3. Fixed some problems with the way updating styles was forcing a
Save in the middle of a UOW, resulting in duplicate DB4O objects.
This is unrelated, but I had to fix it to test the new code.

Change-Id: I01a5dae68322a7431e6edf94ff36d1b2aa74c8ba