Add 3D printing files to download extensions

[nallath]

Description:

Add STL, OBJ, 3MF and PLY to download extensions.

It also re-orders the list to make sure that they are completely alphabetical. Not entirely sure if this is a requirement, but it was almost following it, making it a bit confusing.

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

[michalkleiner]

Hi @nallath! Thanks for creating the PR. We have some failing tests now as when the list is adjusted, the tracker files need to be regenerated. Are you able to do that as well, please? If not, that's ok, just let us know, and one of the team members can look at it at some point.

[nallath]

@michalkleiner I don't actually have a full dev env setup. I did try to run the scripts to minify it, but they need it.

So yeah, I would prefer it if someone could help out with that :)