This pull request is a recreation of #41927, where I accidentally deleted all the code changes.

Pull Request for Issue #23304, only partially.
This PR is based on #38583 and fixes the comments.

Summary of Changes

Adds the ability to batch copy/move tags in the tags list.
Copying a tag also copies its children (same behavior as in other tree models like categories, menues).
Moving a tag also moves its children (same behavior as in other tree models like categories, menues).
For example, it is possible to move a child tag from one parent to another (including its children), or to copy a child tag from one parent to another (including its children).
In the batch tag drop down there is also an item "Root" to move/copy selected tags to the root level.

Changed visualization "Action to Perform" of copy/move action, it is now hidden as long as the user does not touch the select field for copy/move. See example in video below. This change affects batch copy/move dialog of menues and articles as well.

It also fixes a browser console error when the batch dialog is opened and cancel is clicked, on systems where multilingual is disabled.

Testing Instructions

It contains an updated javascript so run: npm run build:js

Initial tag structure for each of the tests below:
Tag1
-Tag2
--Tag3
Tag4

Test 1
Move Tag2 to Tag4 results in:
Tag1
Tag4
-Tag2
--Tag3

Test 2
Move Tag1 to Tag4 results in:
Tag4
-Tag1
--Tag2
---Tag3

Test 3
Copy Tag4 to Tag2 result in:
Tag1
-Tag2
--Tag3
--Tag4 (2)
Tag4

Test 4
Check whether the visualization of "Action to Perform" of copy/move action is first hidden for views like menues, articles. Only if a target item is selected "Action to Perform" appears.

Actual result BEFORE applying this Pull Request

The tags list batch processing does not support copy move.

Expected result AFTER applying this Pull Request

The tags list batch processing supports copy move:

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed