TbSync detection of cloned profile on startup

[jfabini]

TbSync may encounter issues when an existing TB profile is cloned and operated in parallel on multiple systems. The TbSync ID is cloned as part of the repository, but is expected to be unique.

When detecting a cloned profile, TbSync should warn the user - to quote John: "I meant to let TbSync display a warning when it detects it is being run on an imported/cloned profile. (...) The idea to detect a cloned profile import is: Files in the cloned profile have a create-date which is newer than the last logged update performed by TbSync, which usually cannot happen."

The full discussion can be found in https://github.com/jobisoft/TbSync/issues/759 and John's proposed fix in https://github.com/jobisoft/TbSync/issues/759#issuecomment-3481543536