Nits Collected over last month (#595)

- add coverage.out
- add context queue
- fix misspell
- sanitize config: WOODPECKER_GITEA_URL
- storage backend migration should have no xorm session within migration function

cmd/agent/agent.go

@@ -148,7 +148,7 @@ func loop(c *cli.Context) error {
 					return
 				}
 
-				// load enginge (e.g. init api client)
+				// load engine (e.g. init api client)
 				err = engine.Load()
 				if err != nil {
 					log.Error().Err(err).Msg("cannot load backend engine")