Switching to GitHub Flow and tools.build

[TimoKramer]

I am setting up the PR for switching to GitHub Flow and tools.build for the Datahike repository. There is an ADR that I am creating right now that outlines the implications of the switch. In future we will have a main-branch and no development branch. Then new branches are created off of main and merged back into main. A release will be created everytime a PR gets merged into main with an incremented patch-version.
tools.build will be used for the new flow and the corresponding CI-pipeline. You will be able to run the tools inside your repl as well. A big advantage is that maven is not needed anymore to compile the Java-source-code.

I am happy to get feedback on the switch.

[TimoKramer]

#445