Method for deleting tags

[jofwu]

Defunct, unused tags still appear in the tag list and take users to the entry that were formerly associated with even after the tag is removed from entries.

For example: https://wob.coppermind.net/adv_search/?tags=cognitive+realm+132

We need a way to delete tags from the tag list.

[m-strzelczyk]

I can make hard removal of tags a thing as admins-only, as this can mess with entry edit history... Or I could make old, unused tags not display on the tag list and as suggestions for entry and event edition. I think I'll go with the latter option.