[FreddysHouse] Signature Once

Unmaintained [FreddysHouse] Signature Once 1.2.1

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The add-on ID has changed, I recommend un-installing and re-installing rather than updating.

This version adds an "Enable signature once" permission to decide if the user should benefit from add-on.

You will almost certainly want to enable it for all users, but it gives you the flexibility to turn it off for others (e.g. discouraged).

Also fixes an issue where a moderated or deleted post that wasn't actually visible would have the signature on, and all other posts by the user would have it removed.