Groups with same name cause issues

[offtherailz]

Description

If you try to create groups of the same name in the TOC, there are some problems while dragging and moving.

The problem is that the name of the group is used as id (name is the id a group, i think).

Maybe we should generate a unique id (name) for the group, anyway different from any other group in the TOC, and use the title (there is a default title for the localization) to allow the user to ignore this issue and create groups with the same title.

Another solution can be to deny creation 2 groups with same name, but because of nesting, I think It's not the best solution. Users may need to do subgroups like this.

Public Buildings:
 - Type 1
 - Type 2
PrivateBuildings: 
 - Type 1
 - Type 2

In case of Bug (otherwise remove this paragraph)

Browser Affected
any

Steps to reproduce

• create 2 groups with the name "test" in the root (without selecting target group)
• try to drag one of the groups in the default group

Expected Result

• the group is dragged

Current Result

• one of the layers disappears

Other useful information (optional):