Rename "PGE" into "Moondust"

[Wohlstand]

The Moondust is the production title of this project. The "PGE Project" is the working codename that was set after some time of foundation as replacement of initial and bad "PlatGenWohl" title.

It's need to replace the "PGE" with "Moondust" mentioning anywhere: in documents, in printable labels, in translations, etc.

Also, it's need to update application icons with using sketches and drafts (in the _Misc/source_images/Moondust folder) we are made and discussed in some past with @Hoeloe, @Emral and others.

The old "PGE" will be kept for tech purposes (source code, function names, executible filenames) and as convenient mention for internality of the community and dev team., etc.

To do:

• [ ] ~Create a separate branch for rebranding process~ Not needed, as the renaming will go in parallel with main workflow
• [ ] Compose an alternative icons for Editor, Engine, and Calibrator, others are optional (Using sketches in the _Misc/source_images/Moondust)
• [ ] Fetch all in-GUI source strings and translations, and replace "PGE" mentions with "Moondust".
• [ ] Updated help documentations
• [ ] Change the stuff at PGE Wiki
• [ ] Update content of Main Site (wohlsoft-ru)