R1:dd8f588ac51b

Migrate VCS passwords to new shared password infrastructure

Summary:
Ref T13043. Migrate VCS passwords away from their dedicated table to new the new shared infrastructure.

Future changes will migrate account passwords and remove the old table.

Test Plan:
- Ran migrations.
- Cloned with the same password that was configured before the migrations (worked).
- Cloned with a different, invalid password (failed).
- Changed password.
- Cloned with old password (failed).
- Cloned with new password…