feat(BaseSelect): Allow to resize selection

[ledenis]

Hello, I propose this PR to implement the most requested feature (according to the number of 👍) : resize a selection.

1. Use the Rectangle selection tool and select an area
2. Hover the cursor on the bottom right of the selection (the cursor should be changed to the resize cursor)
3. Resize

• Only scaling up is supported
• Only scaling up by whole number (x2, x3, ... xN etc) is supported
• Only implemented for the rectangular selection tool

Try it here !

What do you think?

Fix #741

[grosbouddha]

Thanks for the proposal.
However, we won’t accept UX or major code changes right now until this issue is resolved first: #1246

Also, the resize does not seem to work in the demo above, but the UX idea is still interesting.

[ledenis]

OK, no problem!

Also, the resize does not seem to work in the demo above

Strange, it works on my side 😅

You can check this video. Maybe the dragging experience could be improved indeed, because nothing shows the resize is working if we don't drag far enough.

piskel-resize-selection.webm