Allow separate control of sharing in blog post and main menu

[fo2rist]

Description

1. Use i18n title for share menu Update translation to match current view
2. Make sharing from post body controlled separately from header menu

Motivation and Context

It was impossible to enable sharing from the main menu, but disable in the post.

Side note: Buttons in the post don't really match the light style of the theme, they're quite big and better be placed below the main content.

Screenshots (if appropriate):

The buttons are the same, but I'm not the expert in html/css. Maybe it's better to redesign them completely and make less obtrusive (e.g see reddit, it has a single small nice share button with pop-up menu). Feel free to reach out to me in telegram if you want to discuss any of PRs in real-time

Checklist:

• [ ] I have updated the documentation, as applicable.
• [x] I have updated the theme.toml, as applicable.