Editor: Add Justify option

[KokkieH]

We've received a request to have a Justify button added to the editor toolbar on the app. Currently is only has left, right and center-aligned.

For context, here's a corresponding request to have it added to the block editor on WordPress.com: Automattic/wp-calypso#28696

This is also under discussion for Gutenberg in Core: WordPress/gutenberg#8450

[rachelmcr]

Thanks for reporting the request! I'm going to close this issue because we're tracking alignment issues in each mobile editor repo separately. (Edit: Sorry, I originally linked to an issue in Aztec for iOS here; we don't have an Aztec for Android issue specific to this request but given that the focus is on Gutenberg right now that's the most relevant place to track this going forward.)

For mobile Gutenberg, we are tracking work for an alignment toolbar in the paragraph block here: wordpress-mobile/gutenberg-mobile#170