Display acmx related button only in relevant workspaces.

[mfornet]

Right now buttons to run/compile/upgrade/stress are shown always, even when we are not in a problem/contest.

There are check marks to enable/disable this button, but by default they should not be shown if not in a problem/contest workspace.

[mfornet]

Key binding and other features can also be hidden while the extension is not being used.

https://code.visualstudio.com/docs/getstarted/keybindings#_when-clause-contexts

[mfornet]

I hide buttons by default (they can be enabled in settings). This is temporary while this issue is not fixed.