Support `.config` project directory

[o-l-a-v]

Summary of the new feature

To declutter a project root directory I'd like the ability to put the PSSA config file inside a .config directy, like suggested here (more details):

• Proposal: https://dot-config.github.io/, https://github.com/pi0/config-dir
• Support tracker: `.config` dir support tracker pi0/config-dir#6

One can of course override the config path, but native support for this would be neat.

Proposed technical implementation details (optional)

If running PSSA from project root I'd like it to automatically pick up the config in .config/.

What is the latest version of PSScriptAnalyzer at the point of writing

v1.24.0