[Feature Request] Merge Configuration items

Description When one has a large library, the library can potentially contain similar Tags, Correspondents, File Types, etc. It would be amazing to have the ability to merge these configuration items together. Other Use case scenario: Let's say I have two Tags. Tag A = Insurance. Tag B= Medical Insurance. After having my configuration set for a while, I decide that I want to combine these two tags. User should have the ability to merge or combine these items. Proposed Workflow (not limited to tags). I'm using tags as an example. Administrator is in the Tags setting. Administrator selected multiple tags from the configuration list. Paperless-NGX now displays a new button labeled 'Merge' at the top of the screen next to Permissions and Delete. This should only display when multiple records are selected. When user presses merge, Paperless displays a popup menu with a pulldown menu asking the user which record should be the surviving record. The displayed…