exit the application once watch is stopped

[tadus21]

Fix for PR that I've made couple weeks before. Noticed that my solution actually does not end Run function and the process keeps hanging indefinitely. To fix this added another channel which would notify that the server/process needs to be stopped.

[tadus21]

@Slach don't have permissions to add you as a reviewer so tagging you in the comment

[coveralls]

Pull Request Test Coverage Report for Build 9306204339

Details

• 5 of 10 (50.0%) changed or added relevant lines in 1 file are covered.
• 257 unchanged lines in 10 files lost coverage.
• Overall coverage decreased (-2.0%) to 65.349%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/server/server.go	5	10	50.0%
<!--	Total:	5	10	50.0%	-->

Files with Coverage Reduction	New Missed Lines	%
pkg/backup/restore.go	2	67.08%
pkg/backup/backuper.go	2	65.41%
cmd/clickhouse-backup/main.go	2	77.19%
pkg/storage/object_disk/object_disk.go	5	70.95%
pkg/status/status.go	9	70.2%
pkg/config/config.go	10	70.9%
pkg/storage/general.go	23	61.66%
pkg/server/server.go	23	53.11%
pkg/storage/s3.go	25	43.88%
pkg/storage/gcs.go	156	0.0%
<!--	Total:	257		-->

Totals
Change from base Build 9290182790:	-2.0%
Covered Lines:	8498
Relevant Lines:	13004

---

💛 - Coveralls