Various RTL fixes

[opalmay]

Fixes the following issues on RTL locales:

1. Headers underline now shows on the right
2. Comment actions now show on the left
3. Make visual editor knowledgeable of RTL same way as pages. This fixes multiple issues, like headers underline, and lists rendering on the wrong side/outside of the screen
4. Fix Vuetify margins from right to left and vice versa. Also align modal text right instead of left, shows when updating a page (apparently Vuetify issues)

[opalmay]

I've accidently merged into this branch... So just ignore those please

[NGPixel]

Please mark your other PRs as draft if they are not ready

[LtrDan]

@opalmay Please mark your other PRs as draft if they are not ready:) Will be glad to see this merged!