Expand configuration of direct database connection

This commit introduces the following changes:

1. Deprecating host_no_proxy and port_no_proxy configuration keys.
2. Replacing no_proxy suffix with direct prefix for configuration keys of direct database connection. Considering that the direct database connection can go through a proxy, e.g. pbouncer in session pooling mode, the no_proxy suffix was inaccurate.
3. Adding more options for setting user, password, and dbname of direct database connection. The options were limited to host and port.\

Related to: omnibus-gitlab#6039 (closed)