Accept script-specific parameters from commandline

[WampyCakes]

Description of proposed feature

There ought to be a good way to pass parameters that are not manim flags to a script. I imagine this is its own "section" in the command where these would belong. Maybe after the script and scene name (explicit or implied for scene name)?

How can the new feature be used?

Two immediate use cases that come to mind are:

• Things like generative art or similar concepts where it's ideal to tweak a few parameters in the command to change output
• https://github.com/WampyCakes/manim-rubikscube#putting-it-all-together here I benefited from passing a cube state through the commandline, but manim throws a warning with this approach, making it not an ideal solution.

Additional comments

This should not be worked on until after #1013 is merged.

[WampyCakes]

This may be important per jsonV.

[MrDiver]

• Refactored the Command Line Interface to use Click instead of Argparse #1013
  Is now merged

Related to

• Allow plugins to add custom render CLI flags #1888

Please discuss further implementation of this here and compatibility with the new version of manim