update phpstan to v2

[smhg]

This bumps phpstan and its extensions to version 2.
It also:

• Adds a composer script to run it with composer run stan.
• Fixes some (easy) phpstan warnings.
• Adds the current phpstan baseline to git.
• Adds phpstan to CI.

Please squash the PR if you decide to merge this.

Tagging @SkyFoxvn

[smhg]

@SkyFoxvn can you please re-run CI?
I've moved static analysis (PHPStan) to it's own job to run on just 1 PHP version (currently 8.3). Propel itself does that too.

The reason PHPStan fails on 8.0.2 is that Symfony 6.0.x components are always used on that PHP version.
The CI job labels don't correctly show what actually gets installed.

Thanks!

[smhg]

@SkyFoxvn thanks! Can you please force a CI re-run? It looks like it somehow didn't run on your last commit.

[SkyFoxvn]

@SkyFoxvn thanks! Can you please force a CI re-run? It looks like it somehow didn't run on your last commit.

@smhg well im not sure how to start a new run for pull request(only for branches part of the repo) so i did go to actions and rerun the tests run already created for this branch still ending with error

[smhg]

@SkyFoxvn sorry, I missed an invalid double-declaration of "scripts" in composer.json. Feel free to approve CI. Thanks!