[Tagging] Delete a taxonomy

[bradenmacdonald]

"As a global staff user (instance-level super admin), I can delete a taxonomy."

Acceptance Criteria

1. Global staff users will see this "Delete" menu for non-system taxonomies on the Taxonomy List Page:
   
2. And the same option can be accessed from the Taxonomy Detail Page:
   
3. Clicking that option will reveal this confirmation dialog:
   
4. The "Delete" button will be disabled until/unless users type "DELETE" in the field.
5. Once users click "Delete", the taxonomy will be deleted and a toast shown. If they were on the Taxonomy Detail Page, they are redirected to the Taxonomy List Page.
   
6. Implementing "Undo" as seen above is not required (out of scope). That may come later in [Tagging] Implement Undo framework for taxonomies and tagging #135.

Developer Notes

• Screenshots above are for convenience - Figma is the most up-to-date source for mockups. The scale of UI elements seen in the screenshots above may be incorrect.
• As always, make sure the whole process can be done using only a keyboard.

[ChrisChV]

Once users click "Delete", the taxonomy will be deleted and a toast shown.

@bradenmacdonald The "Undo" functionality of the toast will be implemented in #135?

[bradenmacdonald]

@ChrisChV Yes but that particular story has been postponed, so I'm not sure if/when we'll implement undo.

In any case, you do not need to implement undo as part of this story.