[IMP] Add database settings to use runbot in multi user environment

[ghost]

Hello,

By default, Runbot create and delete a database with the command createdb or dropdb without any configuration (like --port, --host, ...). It means that each database is create on localhost host with the current user.

However, sometime we need to use runbot with an another user or/and with an external database server. To do that, I add 3 parameters in Runbot Settings. The user, the host and the port. With this 3 settings, you can use Runbot with an another user and use an another database server.

These configuration is not mandatory. If the user don't set these settings, nothing change.

I hope you will accept my pull request.

Best regards, Sylvain Van Hoof

[ghost]

Nobody can accept or refuse my pull request ?