* fix: separate signals for passive, active, and forced shutdown
`SIGTERM`: Passive shutdown stopping provisioner daemons from accepting new
jobs but waiting for existing jobs to successfully complete.
`SIGINT` (old existing behavior): Notify provisioner daemons to cancel in-flight jobs, wait 5s for jobs to be exited, then force quit.
`SIGKILL`: Untouched from before, will force-quit.
* Revert dramatic signal changes
* Rename
* Fix shutdown behavior for provisioner daemons
* Add test for graceful shutdown
* Start to port over provisioner daemons PR
* Move to Enterprise
* Begin adding tests for external registration
* Move provisioner daemons query to enterprise
* Move around provisioner daemons schema
* Add tags to provisioner daemons
* make gen
* Add user local provisioner daemons
* Add provisioner daemons
* Add feature for external daemons
* Add command to start a provisioner daemon
* Add provisioner tags to template push and create
* Rename migration files
* Fix tests
* Fix entitlements test
* PR comments
* Update migration
* Fix FE types
* fix: Add `SIGHUP` and `SIGTERM` handling to `coder server`
To prevent additional signals from aborting program execution, signal
handling was moved to the beginning of the main function, this ensures
that signals stays registered for the entire shutdown procedure.
Fixes#1529
Kyle Carberry
Mathias Fredriksson