Multiple panes

[mmalczak]

ARTIQ Pull Request

Description of Changes

Add multiple experiment workspaces.
Add possibility to rename workspace tab. Add tooltip informing about that possibility. Ensure unique tab names.
Opening experiment opens related workspace.
The workspace state is save.
Handle migration of experiments from previous version to the version with multiple workspaces.

Related Issue

Type of Changes

	Type
✓	✨ New feature

Steps (Choose relevant, delete irrelevant before submitting)

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• Check, test, and update the unittests in /artiq/test/ or gateware simulations in /artiq/gateware/test

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Licensing

See copyright & licensing for more info.
ARTIQ files that do not contain a license header are copyrighted by M-Labs Limited and are licensed under LGPLv3+.

[sbourdeauducq]

We don't introduce features like this on a release branch.
#2721 is interesting, thanks for submitting!