Moved repository from Travis to GitHub Actions

[evaherrada]

No description provided.

[sommersoft]

We need to add the Sphinx build step to build.yml, since the Adafruit Bundle has a RTD page. Quick reference:

    - name: Build docs
      working-directory: docs
      run: sphinx-build -E -W -b html . _build/html

Other than that, just need to remove the Community Bundle stuff noted below.

EDIT: sorry about the comment order. I remembered multi-line comment highlights after I purposefully made them in order, and then had to delete them.

[evaherrada]

@sommersoft I think I got everything. Let me know if there's something I missed

[sommersoft]

Thanks @dherrada!

[sommersoft]

Doh! They both do need sudo apt-get install gettext. I completely forgot about mpy-cross needing it. I'll push a PR real quick...

[siddacious]

@sommersoft let me know if there is something I can do to help