Relates to #9948.
When upgrading a project to v2.0, it is important that all source files
are in the same folder. This change makes the upgrade process verify
that this is the case and blocks the upgrade if there are source files
in multiple folders.
Source files are .kmn, .xml (ldml keyboard), .kps, and .model.ts.
Adds actions to support LdmlKeyboardEditor, and refactors and
reorganizes the existing actions along the way to make them clearer.
Compile, Install, and Uninstall supported at this time
