* Change graceful to use a singleton obtained through GetManager instead of a global.
* Graceful: Make TestPullRequests shutdownable
* Graceful: Make the cron tasks graceful
* Graceful: AddTestPullRequest run in graceful ctx
* Graceful: SyncMirrors shutdown
* Graceful: SetDefaultContext for Xorm to be HammerContext
* Avoid starting graceful for migrate commands and checkout
* Graceful: DeliverHooks now can be shutdown
* Fix multiple syncing errors in modules/sync/UniqueQueue & Make UniqueQueue closable
* Begin the process of making the repo indexer shutdown gracefully
* Graceful Shutdown for windows and others
Restructures modules/graceful, adding shutdown for windows, removing and
replacing the old minwinsvc code.
Creates a new waitGroup - terminate which allows for goroutines to
finish up after the shutdown of the servers.
Shutdown and terminate hooks are added for goroutines.
* Remove unused functions - these can be added in a different PR
* Add startup timeout functionality
* Document STARTUP_TIMEOUT
* Prevent deadlock in indexer initialisation during graceful restart
* Move from gracehttp to our own service to add graceful ssh
* Add timeout for start of indexers and make hammer time configurable
* Fix issue with re-initialization in indexer during tests
* move the code to detect use of closed to graceful
* Handle logs gracefully - add a pid suffix just before restart
* Move to using a cond and a holder for indexers
* use time.Since
* Add some comments and attribution
* update modules.txt
* Use zero to disable timeout
* Move RestartProcess to its own file
* Add cleanup routine
