Adopt shared quick pick from platform (Go to line, Go to symbol, Commands)

[bpasero]

This is a result of microsoft/vscode#69955. A couple of quick pick providers will be shared between editor and workbench:

• Go to symbol in file
• Go to line
• Commands

As such the experience has slightly changed:

• there is now also a quick way to switch from one provider to the other in the standalone editor by changing the prefix
• background color is the typical editor widget background
• visually looking the same (e.g. commands keybindings)

All commands have been updated to point to the new solution and the old quick open has been deleted from the standalone editor.

//cc @alexdima @rebornix

[alexdima]

This is great, thank you! 🎉🎉🎉