db/storage: add more metrics to db connection and label by remote server
db/storage: add more metrics to db connection and label by remote server

(cherry picked from commit 85697bbb0a7b42bdd9ec9bd44f04161ec25ee6ff)

tsuru/tsuru,guilhermebr/tsuru,guilhermebr/tsuru,guilhermebr/tsuru,tsuru/tsuru,guilhermebr/tsuru,tsuru/tsuru,tsuru/tsuru