Add job to build and push artifacts

[marohrdanz]

Adding a second job in the workflow to build artifacts and push them to the artifacts repo. These two jobs run sequentially, and the second will only run if the first succeeds.

The two jobs:

1. make_build_tag
   • This job is NOT new; it was added in PR #442
2. build_artifacts
   • New job to build artifacts for Java 8:
     • ShaidyMapGen.jar
     • GalaxyMapGen.jar
     • GUIBuilderMapGen.jar
     • ngchmWidget-min.js
     • ngchmEmbed-min.js
     • WebContent/ngChmApp.html
     • WebContent/server.app (directory)
   • Commits, tags, and pushes to NG-CHM-Artifacts repo
     • Uses same tag name as step 1
     • Assumes the directory structure from NG-CHM-Artifacts PR 1

Additional related changes:

• Changes file name 'BuilderMapGen.jar' -> 'GUIBuilderMapGen.jar' (cbe0821)
• Changes file name: 'build_mapgen.xml' -> build_guibuildermapgen.jar' (cbe0821)
• Adds git tag as comment to .js files (ccd5cc5)
• Adds git commit hash and tag to MANIFEST of jar files (81a9092)
• Adds git commit hash and tag to .txt file in server.app and WebContent (ca73a1e)

For reference, I used my forks to test the jobs in this repo. Forks:

• marohrdanz/NG-CHM fork
• marohrdanz/NG-CHM-Artifacts fork