Implement `-q[l|m|h|p|k]` to specify render quality

[leotrs]

Forked from #65.

Instead of -l being the abbreviation of --low_quality, we should have -ql, and similarly so for medium/high/production/4k quality. Also, we should have a --production_quality flag.

[leotrs]

This is a fairly easy PR now that #98 has been merged. Any takers?

[jvdoorn]

I can take a look at this, I assume that production_quality is higher quality than fourk_quality?

[leotrs]

Thanks @jvdoorn for volunteering! You can see what each quality means in https://github.com/ManimCommunity/manim/blob/master/manim/config/default.cfg. The "production" quality is defined under the [CLI] section, as frame_rate = 60 pixel_height = 1080, pixel_width = 1920. The other four have their own sections [low_quality], etc.

[naveen521kk]

Is this fixed?

[jvdoorn]

Yes except for the -qp flag, however since that is default behavior I personally don't see a use for it. It could however be implemented very easily if you want. Otherwise this issue is done and dusted.