Fixes the pullquote color setting by moving `color` from `blockquote p` to `blockquote`. Also adds the border-left to the front-end stylesheet to match the editor. Also adds styles for rtl pullquote.
Props kokkieh, desrosj, mukesh27, khushbu19, disillusia, aliveic, abrightclearweb, SergeyBiryukov.
Fixes#47019.
Built from https://develop.svn.wordpress.org/trunk@47273
git-svn-id: http://core.svn.wordpress.org/trunk@47073 1a063a9b-81f0-0310-95a4-ce76da25c4cd