Achieve check feature parity with plugin review team's current tool

[felixarntz]

Is your enhancement related to a problem? Please describe.

Reviewing https://github.com/WordPress/plugin-check/commits/trunk, several check related changes have landed in the past 2 weeks that should be incorporated into our plugin checker for parity.

Each of the below top-level bullet points should preferably be addressed in its own PR:

• Update severity of certain checks in Plugin_Readme_Check to "error" (see c5d539b).
• Update Plugin Check Review PHPCS XML file related to Plugin_Review_PHPCS_Check with latest changes from 5939831, ee56bc2, and 542ea3c.
• Add application files support to File_Type_Check (see b081cf7).
• Implement new check for plugin trademark violations (see f15d41c).

cc @eclarke1 @joemcgill @bordoni

Designs

No response

Describe alternatives you've considered

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[bordoni]

Thank you for logging this here.
I will start porting over the code into the branch later today, so we can reference the old code from this repo.

[bordoni]

All of the code from our legacy plugin repository is now living here on the legacy-plugin branch.

Sorry for the random mentions that were made once the commits were ported, since the hashtag mentions were to the old issues and PRs.

I will manually release version 0.2.0 this week to the WP.org, once we the Plugin Review team is ok with a launch date.

[bordoni]

We are live with version 0.2.0 on WordPress.org.

https://wordpress.org/plugins/plugin-check/