[Feature Request] Add support for Google Assistant "Read It"

# Issue details
I would like to be able to use google assistant to read article aloud from wallabag.

Basically how it works is you can activate google assistant (by hey google or other methods) and say "read it" then android assistant will start reading the article aloud. For me, it is a little better than listening using the default TTS engine since this has a higher quality voice.

Dev docs:
https://developers.google.com/assistant/app/read-it

Article with more info:
https://www.androidpolice.com/2021/04/27/google-assistants-web-page-reading-tool-gets-a-visual-makeover/

### Duplicate?
Didn't see any related issue.

# Your experience with wallabag Android app
Honestly, I freaking love the wallabag app. Sure, it has some rough edges but I use it every day and 99% of the time it works just the way I want to. One thing I particular appreciate is how easy it is to use tags! :)