Add gender presentation pride flags

[ngkz]

Description

Add gender non-conforming, femboy and tomboy flags

Features

Issues

• Some colors of GNC and tomboy flags are off
• two purples of the GNC flag are hard to distinguish

TODO

[hykilpikonna]

Thank you for the PR!

The flags look good on the preview page, but due to color lightness adjustments, the two purples look kind of the same.

However, since the lightness range between the brightest and dimmest colors is too wide, lightness adjustment is necessary (or else it would look like the below screenshot where the dark purple isn't really visible on dark terminal, and the white wouldn't be visible on light terminals.

I'll merge this for now, even though the colors will look like this until we have a better way of addressing the lightness issue.