Add block quote format for emphasis to wysiwyg editor

## Description

Client asking to have the ability cite and quote text.

To add a vertical grey bar to the side of text, use a > followed by a space in front of the text. For example:

> To semantically and visually cite text

# Context

https://cds-snc.freshdesk.com/a/tickets/18070
#3951
https://github.com/cds-snc/platform-forms-client/pull/5265