:sparkles: added a --mysql-socket option to connect to MySQL using a Unix socket

[mackuba]

Description

This adds a --mysql-socket option to the CLI which passes a unix_socket parameter to the MySQL Connector, which lets you connect using a Unix socket instead of a TCP port.

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

Tested with my local database with disabled networking (MacPorts default), with and without the option --mysql-socket /opt/local/var/run/mysql8/mysqld.sock.

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules