embed build script version in its file; add zip-packages job to CI; split workflows

[TheElan]

This adds workflows for:

• build script version maintenance
• starter and migration zip releasing

it also splits existing into two phases: build PR and build and release Master, so tag release won't trigger on each branch commit

[TheElan]

after this is merged old workflows probably should be disabled: https://github.com/SinTh0r4s/ExampleMod1.7.10/actions/workflows/gradle.yml

[SinTh0r4s]

Implemented updateGTNHBuildScript gradle task. It will only run if specifically called and show up under forgegradle: