Add some usages needed for ChromeOS hosts

[spidey3]

Description

This adds two Consumer Page usages that are used often in ChromeOS.

• AL_CONTROL_PANEL (0x19F) - On ChromeOS this opens the settings tray.
• AL_ASSISTANT (0x1CB) - On ChromeOS this starts the Google Assistant.

Many Chromebooks have dedicated keys for these; this will allow them in QMK.

Note, owing the the shortage of available KC_ keycodes, there is no mapping to these now. To use them, you will need to implement your own custom keycode, and can call this to send the code:

if (record->event.pressed) {
    host_consumer_send(AL_ASSISTANT);
} else {
    host_consumer_send(0);
}

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[fauxpark]

Thanks!