MM-11262: database config store (#10281)

* vendor github.com/jmoiron/sqlx

* MM-11262: introduce a database store

* revert unnecessary fmt.Errorf

* simplify unit test helper methods

* remote TODO re: retry

* relocate initializeConfigurationsTable for clarity

* factor out a commonStore

* acquire database config lock on close for safety

* add missing header

* fix lock comment

web/web_test.go

@@ -47,7 +47,7 @@ func Setup() *TestHelper {
 		panic(err)
 	}
 
-	options := []app.Option{app.ConfigFile(tempConfig.Name(), false)}
+	options := []app.Option{app.Config(tempConfig.Name(), false)}
 	options = append(options, app.StoreOverride(mainHelper.Store))
 
 	s, err := app.NewServer(options...)