Revert mysql port property back to the standard MySQL default of 3306.
Revert mysql port property back to the standard MySQL default of 3306.

I (Randy Kerber) had changed it to 3006 for Open PHACTS because the
Docker setup for openphacts was looking for mysql on port 3006.
But other users of BridgeDb might be relying on the old default of 3306.

bridgedb/BridgeDb,egonw/BridgeDb,bridgedb/BridgeDb,egonw/BridgeDb,egonw/BridgeDb,bridgedb/BridgeDb,bridgedb/BridgeDb,egonw/BridgeDb,bridgedb/BridgeDb,egonw/BridgeDb