Automate png crush

[BlckHawker]

Unsure if this would be handled by KTANEWeb or another application entirely. While the maintainer checklist recommends people to use png crush to optimize file sizes, I (and I assume other maintainers) forget this step. While this has no consequences when missed occasionally, it can cause issues as the repo grows. It would be nice if the entire repo went through png crush to verify all files are compressed. However, that will take a long time, and shouldn't be done too frequently as the size saved would be minimal. I believe once every 6 - 12 months should be fine. This would be nice if it was done automatically and PR created to target main so contributors are not waiting hours to compress manually.

[Luminoscity]

Just a few comments on this idea.
Pngcrush isn't perfect. Sometimes the images even come out larger than they were originally, even with the brute force option. And sometimes the crushing process ends up changing the visuals of the image in a detrimental way.