Add option to only send clipboard on intent

Summary

This adds an option to the clipboard plugin to only send on intent. It adds 2 cli options, a button to the plasmoid, and a button to the app. It adds a cli option and buttons to the plasmoid, app, and indicator.

Implements 386568 and 392164

Test Plan

I manually tested existing and added clipboard plugin features

Send using app:

Send using plasmoid:

Send using indicator:

Send using cli:

/usr/bin/kdeconnect-cli -n 'My Untrusted Device' --clipboard