You can now set your quote posting privacy preferences on Mastodon. You can allow anyone / just your followers / nobody to quote you:
1. Log into your server's website
2. Click ⚙️ Preferences (if you're on a phone it's ☰ in bottom right and ⚙️ Preferences)
3. Click "Other" (if you're on a phone it's ☰ in top right and "Other")
4. On "Who Can Quote" menu select option you want
5. Click "Save Changes" button
The actual ability to quote post will be in the next Mastodon update.