docs(examples): add descriptions and update theme

[joshka]

Fixes #401

• docs(examples): add descriptions and update theme
  Use the OceanicMaterial consistently in examples

• docs(examples): move example gifs to github
  A new orphan branch named "images" is created to store the example images

See https://github.com/ratatui-org/ratatui/tree/images

[codecov]

Codecov Report

Merging #460 (c623cc8) into main (0696f48) will not change coverage.
Report is 8 commits behind head on main.
The diff coverage is n/a.

❗ Current head c623cc8 differs from pull request most recent head bb14d77. Consider uploading reports for the commit bb14d77 to get more accurate results

@@           Coverage Diff           @@
##             main     #460   +/-   ##
=======================================
  Coverage   90.00%   90.00%           
=======================================
  Files          40       40           
  Lines       11156    11156           
=======================================
  Hits        10041    10041           
  Misses       1115     1115           

[orhun]

LGTM, should we also auto-generate GIFs on that branch?

[joshka]

Definitely worth doing sometime, but there doesn't seem to be an easy way to only generate the gif that has changed, so manual works for the short term.

[orhun]

Uhm, why this was closed?

[joshka]

We were modifying the merge settings at the time (as rebasing doesn't work with signed commits), and I merged this manually (so the two commits would be separate rather than squashed).
Just joshka@ca9bcd3 and joshka@5c785b2 are merged (not the extraneous bb14d77)