Fix CLI bugs

[jsonvillanueva]

Changelog / Overview

• Fixed conflict with -f which was previously assigned to both --show_in_file_browser and --format by removing -f from --format. A warning is issued that -f will soon move to --format.
• Added back in flags to render the files as gif/last frame. Deprecated them in favor of --format.
• Fixed the broken --output_file/-o option.
• Fixed an issue where the -qh quality option was interpreted as -q -h, prompting the help page.

Motivation

The format of the Scene(s) to render should be easily decidable under a single option: -f or --format.
As such, rendered media can now be selected via manim -f png [FILE], or more explicitly manim --format=gif [FILE]

Testing Status

Further Comments

It'd be nice to have this in the release so that we're not knowingly releasing a buggy new CLI, but I wish I had more time to implement test cases for this PR. If test cases are preferable, we can make a patch release later.

Checklist

• I have read the Contributing Guidelines
• I have written a descriptive PR title (see top of PR template for examples)
• I have written a changelog entry for the PR or deem it unnecessary

Reviewer Checklist

• The PR title is descriptive enough
• The PR is labeled correctly
• The changelog entry is completed if necessary
• Newly added functions/classes either have a docstring or are private
• Newly added functions/classes have tests added and (optional) examples in the docs
• Newly added documentation builds, looks correctly formatted, and adds no additional build warnings

[behackl]

Read the code, LGTM. (Didn't test locally yet, if someone else manages to use these changes successfully, we can merge it.)

[behackl]

One thing I noticed, please have a look. I think we can merge this after this discussion is resolved.

[naveen521kk]

lgtm