Move supported platforms table to own file

[faern]

When we get questions about what platforms we support, the answer is a bit "it depends". There is usually one OS version defined in various metadata as the lower bound. There is one version of the OS we print on the website. There is a combinations of OS versions and target architectures we actually run e2e tests against etc.

What versions our e2e tests are running against is not very easy to find information overall, so it's nice to bring that data into the open as well and make it easier to find both for people internally and externally.

This PR aims to clarify these things better by moving the supported platforms table to its own markdown file and expand the scope significantly. But there is a balance to be found here, we don't want the file to get outdated too often or needing too much manual work all the time. So we should not specify in detail minor/patch versions of OSes etc.

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[faern]

@faern made 1 comment.
Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion.

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docs/supported-platforms.md line 20 at r1 (raw file):

## Windows

Supported versions: 10 (Version 19H2 and newer) and 11. Both x64 and arm64.

The Version 19H2 was just a number I randomly picked to show that I think it would be good if we actually specified a lower bound, given that "windows 10" is very very vague given how long it has existed and how many versions of it there are.

I have brought this up in the past as well. But I think it's important that we do run the full e2e test suite on the oldest version we support on Windows (and all other platforms as well for that matter).

We don't need to do extremely extensive research to find out what the oldest version that the app actually works on currently is. We can just pick an old enough version that we know works, make sure we run testing on that specific version, and then specify that as the lower bound. As the top of the document says: It might work on many more versions, but we don't give any guarantees about it.

[faern]

@faern made 1 comment.
Reviewable status: 0 of 2 files reviewed, 2 unresolved discussions.

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docs/supported-platforms.md line 22 at r1 (raw file):

Supported versions: 10 (Version 19H2 and newer) and 11. Both x64 and arm64.

### Tested versions

It would be good if the new supported platforms docs could reference to where the tested platforms are actually defined. For example for the desktop platforms that would be "<some config file path> on the end to end testing server" or something like that.

And the opposite. Wherever each team actually define the test runner targets, leave a comment about that that file should stay in sync with this document.