Create xontrib

[anki-code]

Hello @2xlink! Thank you for great idea! It works! Let's create complete xonsh xontrib from this!

In this PR I created complete xontrib structure. You can pull and run:

git clone -b xontrib https://github.com/anki-code/xonsh-remote-dir-tabcomplete
cd xonsh-remote-dir-tabcomplete
pip install -U .
xontrib load remote_dir_tabcomplete
rsync myhost:~/<tab>

Next merge the PR.

To finish the work I need some actions from you:

• It's a good practice to add xontrib- prefix before the name of your repository. It allows use the Github search to find it. Please rename the repository to xontrib-remote-dir-tabcomplete (the xonsh-remote-dir-tabcomplete will be redirected to it automatically).

• Add "xontrib" topic to the repository. You already have "xonsh" topic but having both "xonsh" and "xontrib" much better.

• Publish your xontrib to PyPi in 5 minutes. Users can install your xontrib via pip install xontrib-remote-dir-tabcomplete. Easiest way to achieve it is to use Github Actions:

1. Register to https://pypi.org/ and create API token.
2. Go to repository "Settings" - "Secrets" and add keys PYPI_USERNAME and PYPI_PASSWORD.
3. Click "Actions" link on your Github repository.
4. Click "Set up this workflow" on "Publish Python Action".
5. Commit the config without any changes.
6. Now when you create new Release (release name and tag should be 0.0.1 for now, see it in setup.cfg) the Github Actions will publish the xontrib to PyPi automatically. Release status will be in Actions sction.

• Optionally you can add preview image with common screenshot to get more attention in xontrib Github topic.

Thanks!