[Feature Request] Add dummy testing mode

[MultisampledNight]

Is your feature request related to a problem? Please describe.
Sometimes on the Discord server when reporting segfaults or other, difficult-to-debug problems, I'd like to attach a trace made with rr which would let the program replay like a video record. Unfortunately Rare contains confidential data like an API token, which makes this kind of debug help more dangerous than useful.

Describe the solution you'd like
A command-line argument or even a global in the source code which makes Rare truly an UI, without ever actually interacting with legendary (and reading in files with confidential content). In this mode, Rare inserts a few mock games into the list and similarly where else appropriate, which behave like normal games would if they'd be actually installed/uninstalled/launched/moved/repaired/deleted/etc.

This would not only offer a safe ground for in-depth traces, but also would make reproducing issues easier. For example, if Rare would have a general issue with game handling which is reproducible in that dummy mode, then everyone interested in debugging could easily test in the dummy mode even without logging into EGS. On the other hand, if it's not reproducible in the dummy mode, then it's obvious something is wrong with the game itself.

While this mode would offer some advantages, it might also be quite an effort and difficult to implement properly.

Describe alternatives you've considered
None.

[Dummerle]

I like the idea, but the implementation would be much work. I will see, what I can do

[MultisampledNight]

...I just had the very weird idea that if implementing it on the Rare level is too intrigued, we could maybe implement an HTTP server returning dummy data on API calls. This way legendary could also be tested indirectly.

[loathingKernel]

Actually this could work much better than adding dummy mode on Rare