Migrate from rst2ansi to rich

[ezzieyguywuf]

Closes #1103

[ezzieyguywuf]

@olzhasar-reef pinging you since you were active in #1103 and it seems you have commit privaleges to the repo, hoping you can take a look.

[ppolewicz]

Won't that break rendering docs with sphinx on readthedocs?

[ezzieyguywuf]

looks like sphinx supports markdown I'll find some time to test how this renders and whether other changes are needed for sphinx

[ezzieyguywuf]

@ppolewicz so you're right, the markdown stuff did break sphinx, and while I went down the rabbit hole of resolving it, turns out that rich actually can work with rst, it just needs an extra plugin.

so I've reworked this to leave the rst as-is and instead just migrate away from rst2ansi and to rich.