gui: Add shortcuts for tab tools

Summary:
PR description:

This makes accessing the RPC console very fast/easy. It also improves accessibility.

This is a backport of Core PR15756

Test Plan:
ninja && src/qt/bitcoin-qt
Test the 4 key sequence shortcuts from the main window. They should open the debug (rpcconsole) dialog and show a specific tab.

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, deadalnix

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D8148