Bulk-assign recipes to tags/categories

[theNizo]

(I will mostly explain just using the word "Tag", because it's easier. I actually mean "tag" AS WELL AS "category", while keeping in mind that categories work a little different.)

Is your feature request related to a problem? Please describe.

I came up with a tag and want to assign it to multiple recipes that already exist.

I need to click on each recipe, edit it, type in the tag, save, go to the next recipe, etc. This takes a lot of time.

Currently, the only way to assign tags is Recipe -> Edit -> Add Tags

Describe the solution you'd like

I want to do Tag -> Edit -> Assign recipes

Pretty much the inverted thing of what we already have.

You can only assign one category per recipe. In this case, I'd prefer to be told visually (eg. red colored text) that a recipe is already assigned to another category, but still be able to add them (and therefore CHANGE the category).

Describe alternatives you've considered

Editing the source files via script (is not a viable option for a normal user).

Grey out recipes that are already assigned to a category. The user wouldn't be able to make mistakes as easily, but they would have to remove the already existing category by hand before being able to select the recipe in the list.

---

For being able to edit tags, there could be a connection to #682 and parts of #1244