Implement grid mode clip edit & launch - feedback appreciated. Implements #1909

[RJ-Eckie]

This implements a way to edit and launch a clip in grid mode with one action.

Changes to edit mode:

Edit mode is now either launching or non-launching:

• Blue: non-launching (unchanged)
• Cyan: identical to blue, but whenever a clip is entered that clip is also launched (quantized, or immediately when holding shift)

Launching/non-launching mode can be toggled by pressing green+blue at the same time
Launching is quantized. (Immediate launching with shift+cyan to be implemented.)

Changes to copying in grid mode:

Copying now has three variants:

• Launch mode: after copying, remain in grid view (unchanged)
• Edit mode, non-launching: after copying, enters newly created clip
• Edit mode, launching: after copying, enters newly created clip and launches it

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This addresses all complaints in #1909 and even goes a step further. Especially when copying + launching it feels really smooth! Interested to hear what other people think.

[github-actions]

Test Results

103 tests  ±0   103 ✅ ±0   0s ⏱️ ±0s
 15 suites ±0     0 💤 ±0 
 15 files   ±0     0 ❌ ±0 

Results for commit a012c0b. ± Comparison against base commit abe9158.

♻️ This comment has been updated with latest results.

[RJ-Eckie]

Ready for review as far as I'm concerned. Happy to make changes if there's feedback.