Add keybindings for popup and decryption picker

[kkuehlz]

• Activate decryption element picker : Alt+Shift+D
• Activate popup: Alt+Shift+Z

Submitter Checklist

• [x] Verified that all lint errors/warnings are resolved (npm run lint)
• [x] Tested on Firefox (npm run firefox)
• [x] Tested on Chromium (npm run chromium)

[kkuehlz]

cc @cg505

You were interested in this functionality. Let me know if this is what you wanted.

[stsushi]

get that fermented baked grain product!