feat: return different exits code on DB vacuum failure

[jakubgs]

Problem

When there's not enough disk space for an SQLite DB vacuuming node gets into a restart loop.

2023-10-09T07:13:54.366Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}
2023-10-09T07:25:36.009Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}
2023-10-09T07:38:52.551Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}
2023-10-09T07:50:36.884Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}
2023-10-09T08:02:52.289Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}
2023-10-09T08:25:38.890Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}
2023-10-09T08:40:14.657Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}
2023-10-09T08:51:37.570Z INFO gowaku.db-setup#011sqlite/sqlite.go:34#011starting sqlite database vacuuming#011{"node": "16Uiu2HAmKTYnoPKebjWy63e1zPKiYRCQvm25W5mNSnCFE8EmzLga"}

Suggested solution

Use a separate exit code like 166 we could then use the RestartPreventExitStatus Systemd config to stop the service restart loop.

You can see a list of exit codes used by POSIX and Systemd here:
https://tldp.org/LDP/abs/html/exitcodes.html
https://freedesktop.org/software/systemd/man/systemd.exec.html#Process%20Exit%20Codes

Alternatives considered

Detect how much disk space is left? Overly complex.