[UNREAL] Configure GHA Release Pipeline

We need to:

[X] Parameterize the beam-init-game-maker.sh with the PATH_TO_OUR_CLONED_REPO_IN_THE_CUSTOMER_PC such that we can handle the Plugin copy/pasting and .uproject editing via this script (ideally we should try copy pasting the BeamableCore code into their Target.cs file too).
[X] Set up GHA to get whichever version is written in the .config/dotnet-tools.json and copy it over into the beam-init-game-maker.sh script.
[x] Fix the github runners lack of disk space issue when running Linux and Windows builds. Try to investigate and solve this, but... if you end up needing a self-hosted running, talk to @Brandoffsky.
[ ] Set up GHA to package things up in zipped files and create a GitHub Release (prepare_release.yml).
- https://trstringer.com/github-actions-create-release-upload-artifacts/
- https://github.com/ncipollo/release-action

Things to note:

Read the Beamable Developer Guide markdown file in the docs inside the UnrealSDK repo for a better understanding of what is the definition of done here: it should be the case that the entirety of the guide is true.
If any changes are made to any of the workflows, please write comments that explain why the new thing is needed and what it does.
Please update the Beamable Developer Guide in the docs folder to match any changes.

beamable / UnrealSDK