Action node UI improvements for scalability

[mewa1024]

Issues:

• it's long and hard to find things
• some items in appear in multiple categories (e.g., OAuth)
• there is no distinction between native actions and actions added by packages

Suggestions:

• add a search field above at the top of the menu (TJ actually built this as part of the Jan 2021 hackathon)
• have some convention for actions added by packages, such as font style, meta-text, separate menu?* (* do we control where actions from packages go, or is that controlled by the package author?) related Composer Action menu should group custom actions by dotted paths. #6282 ,

Converted to issue #8254

[mewa1024]

Example: Action added from Telephony package

[mewa1024]

@vivekkshankar