[D8] Keep a snapshot of configuration directory in database

Description of the need

Odds are that some day someone will mess with active config directory by either improperly editing files or getting them deleted. And it won't be a trivial task to bring such a broken website back to functional state in case if no backups were taken to restore from.

Proposed solution

What if Backdrop could take a snapshot of the configuration directory on each cron and keep it updated and saved in the database, and use it to re-create configuration directory content in case if it is missing or broken?

Real-life case

Some relevant quotes from real-life case on Gitter of November 17, 2019 4:28 PM:

@alanmels: @serundeputy, this made me think: why don't we keep a snapshot of config files in DB just in case if the directory or some config files get deleted?

@serundeputy: maybe not a bad idea; prolly experiment w/ a contrib module and if it is working well and proven we could make a case for core i think there may be a core issue already about autobackups already; so we should read what is in there too

The closest one I could find in core issues is probably https://github.com/backdrop/backdrop-issues/issues/2409, but its subject is different. So I've decided to create a new feature request just in case if it's worth considering and implementing.