New Concept: Internal plugs

Added "internal plugs," which allow actions to be taken on an existing post with multiple accounts.
The first plugs I created is "repost".
If you post something on X, you can get other people to repost it after X amount of time.

What's Changed

• Internal plugs by @nevo-david in #500

Full Changelog: v1.14.1...v1.15.1