Adding release info to the editor (app) and games

A ReleaseInfo (with json schema) has been created to store information about the release: appVesion (version of the editor e.g. 2.0.0) and releaseType (canary|dev|stable|beta). The "dev" option is only needed for our working copies to work (what is in the repo cannot be considered a release).

Ivan, this file should be generated automatically each time a new release is created. Could you please take a look and see if that can be done? Thanks!
See https://github.com/jtorrente/ead/blob/editor-releaseinfo/assets/appdata/release.json for an example of what the file looks like and where it is supposed to be stored (/appdata/release.json). json schema here: https://github.com/jtorrente/ead/blob/editor-releaseinfo/build-tools/generators/src/main/resources/appdata/release.json

Also: The editor saves the appVersion into EditorGame