Add a status endpoint that attempts to connect to mysql and fails if the connection pool is full

[ansell]

Since caching the logger resources paths in nginx has been enabled, the ALA monitoring software will not show when the mysql connection pool fills up, hiding downtime. There needs to be a new status endpoint that attempts to connect to mysql without perform any queries, and immediately returns an error to the request if the connection failed, to enable the monitoring software to flag the events when the mysql connection pool gets full because of full table locks used by backup software.