feat: Allow run plugin to be used as a package manager

[EyeCantCU]

This adds an install function to run that allows it to be used as a package manager on the package screen, providing categorizations of various commands

It does so by treating the passed command as a package from where the run plugin then executes it

Example:

  ...
  package_manager: yafti.plugin.run
    groups:
      Simple commands:
      - Hello World: echo 'Hello, World'
  ...

Result: 'Hello, World' is output in the console

[marcoceppi]

This makes a lot of assumptions (like the package keyword). I'd rather move away from using the .install method and instead use .__call__. However, that breaks other things / assumptions in the Package Install screen. The truth is there's no real good way to make this work in a short period of time so I'm going to land this and I'll open a v1.0 issue to make plugins and package install screen work better together.