storage: Expose Stratis virtual filesystem sizes

[mvollmer]

Instead of the "Managed filesystem sizes" concept. This makes Cockpit
easier to discover when you know the real Stratis concepts and exposes
its full capabilities.

Demo: https://youtu.be/E1zqhAowus8
Longer exploration: https://youtu.be/1W6QPNPwT7Q

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Storage: Support for managing virtual Stratis filesystem sizes

Cockpit now directly exposes the --size and --size-limit options of the stratis filesystem create command as well as the stratis filesystem set-size-limit and stratis filesystem unset-size-limit commands.

[mvollmer]

Let's get this in. The UI here assumes that people are experts in Stratis and know exactly what they are doing and don't need any help or explanations from Cockpit. If that's not good enough, then we have to kill this. I am not going to work on this much more.

[jelly]

No strong argument against or for. There is one tiny codeql warning however which seems nice to fix.

[mvollmer]

No strong argument against or for.

Yeah, it's meh all around.

There is one tiny codeql warning however which seems nice to fix.

There's lots of linting to be done, but I think the Variable m is not used. warning has been fixed.

[mvollmer]

but I think the Variable m is not used. warning has been fixed.

Ohh: there were two "unused m" warnings, and I only fixed one, but the comments here show the wrong one as fixed! I am always suprised at how fragile these shiny web things actually are.

[cockpituous]

This added line is not executed by any test.