Actions workflow for building and updating docs

[J0B10]

Workflow that automatically updates the docs once files are pushed to master.

Needs to be tested locally using phishy/wflow or nektos/act.

Also the private access tokens for the docs repo must be generated and added as secrets to the repo as ${{ github.token }} only has acces to the nodecg-io repo.

[J0B10]

I tried to test it but I couldn't get docker to run on my windows machine as I have Windows 10 Home with update 1906 and docker requires a Pro / Enterprise / Education or Home update 2004 (which unfortunatly isn't available for my device yet).
This is couased by Hyper-V being not supported on these operating systems and WSL2 being not available. For more information on this see Install Docker Desktop on Windows and https://docs.docker.com/docker-for-windows/install-windows-home/

If somebody has docker working and set up and is familliar with github actions I'dd be happy if you could save me a lot of work by testing this.

If nobody is found I'll need to test if I can get this to work on a linux system.

[hlxid]

I couldn't get this working with either act or wflow. Both failed at the setup-python action.
From looking at the workflow file the python script should work, but according to the ad-m/github-push-actions Readme we need to manually commit and the action just pushes.

[hlxid]

Other than the two review comments this looks good to me.