feat: add prometheus metrics to database.Store (#7713)

* Adds dbmetrics package and wraps database.Store with a Prometheus HistogramVec of timings.
* Adds Wrappers method to database.Store to avoid double-wrapping interfaces
* Fixes test flake in TestLicensesListFake

coderd/database/dbfake/databasefake.go

@@ -97,6 +97,10 @@ type fakeQuerier struct {
 	*data
 }
 
+func (*fakeQuerier) Wrappers() []string {
+	return []string{}
+}
+
 type fakeTx struct {
 	*fakeQuerier
 	locks map[int64]struct{}