Remove `autoplay` CLI argument

[dan-niles]

• Remove --autoplay CLI argument and set videos to always autoplay.
• Remove some unused files from the templates/assets folder.

Closes #233

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 1.62%. Comparing base (bb26bfb) to head (a8552d8).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #244 +/- ## ===================================== Coverage 1.62% 1.62% ===================================== Files 11 11 Lines 1049 1047 -2 Branches 158 158 ===================================== Hits 17 17 + Misses 1032 1029 -3 - Partials 0 1 +1 ```

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