Create a Release workflow to publish new Source build artefacts

[traunts]

Extend the existing build script to version the engine, build the artefacts and publish a release.
The intent is to use the semantic-release package, with supporting plugins to automate version numbering and release publishing

Steps:

• Ensure that the workflow is able to distinguish between and handle releases from the master branch and prereleases from the development branch.
• Configure semantic release with plugins to generate version numbers
  Requires the export-data plugin (linked above), dry-run as a step before building to write the version number before compilation.
• Add workflow steps to write new version numbers to source code files before build.
  Need to edit Constants.h, containing the c_GameVersion field.
• Add a new workflow job dependent on both build jobs that:
  • Downloads the build job artefacts
  • Runs semantic-release to package the release files, generate git tags, commit the changed version files & tag, and publish a new release.