Move to Github actions and remove CircleCI

[dsilhavy]

Description

We currently have a mix of CI/CD platforms. For the deployment of new versions, we already use GitHub actions. For unit and functional testing of the pull requests, we use CircleCI.

Todos

Move completely to GitHub for all CI/CD related jobs. That requires us to run the jobs defined in https://github.com/Dash-Industry-Forum/dash.js/blob/development/.circleci/config.yml as GitHub actions. The corresponding workflows need to be defined.