snap: Add user facing support documentation

[popey]

On the snapcraft forum, some common support questions are beginning to surface. We spend time debugging and answering the questions when they should really be documented. Here'a a few:

• Can't install snap

  • Is it available in this region (some countries are geo blocked for support or political reasons)
  • Sometimes the snap is only available for certain architectures
  • Maybe the snap is private

• Snap is outdated

  • How do I find out who maintains a snap?
  • Where do I file a bug against a snap?

A central support document which has some common support questions and answers we could point to (and would turn up on internet search) might be useful?

[iyissa]

Hello, Can I work on this if nobody has taken it up?

[degville]

Hi @iyissa! Thanks for your interest in this. And yes, of course. That would be really helpful.

We do have a Fix common issues page, which might be the best place to add this kind of information - what do you think? And if this seems suitable, would you prefer for me to move that document into this repository so we can work on it here?

Big thanks to @popey for creating this issue.

[iyissa]

Hello @degville

I agree the Fix common issues page is the best place to add this kind of information. Sure, moving the document into this repository will be great for us to be able to work on it.