lorri pause, lorri unpause

[Profpatsch]

Lorri should have a pause and an unpause subcommands.

• The pause command should apply to the selected nix file, by default ./shell.nix.
  • It should stop the triggering of any reevaluations/rebuilds until the nix file is unpaused
  • It should print an information for lorri direnv that the nix file watching is paused, but we are still loading the last known state before pausing (with a timestamp of when this version is from).
• The unpause command should reactivate the default rebuild-on-watch-change behavior.

Bonus:

• lorri will detect whether something has changed in the meantime (by continuing watching the project and setting a marker as soon as something changes), and immediately schedule a rebuild on unpause.

Questions:

• Does/should pausing influence any other modes, like lorri shell or lorri watch?
• Should we put the commands into a lorri experimental … subcommand first until we are sure they work as intended?

[nyarly]

I'd love to see this implemented, but agree that experimental/internal make sense to reduce the number of semver changes required.