add exist rack to data center room

We experience the same missing add/edit functionalities all over the "Racks" functionality. Some of theme were apparently "lost" during the integration of the racks plugin into the core.

• in the room view shown by @DY90 you see " elements are out of room bounds" but are not able to associate them to a room.
• In the Rack view, List view, you are not able to add a Item/Computer,...

The most requested missing feature is however:

• Defining the Rack in the Computer (or other asset) view. This is imho https://github.com/glpi-project/glpi/issues/4646 but was never correctly addressed. If a computer is associated to a rack, you see the datacenter position, but are not able to edit it. If an asset is not assigned to any rack you have no possibility of assigning it except going to the Rack view and searching the device again. WIth the "old" rack plugin, this was possible through the Racks menu on the left.
•  

concretely, adding the possibility to open .../item_rack.form.php  from within an asset would address this issue.

Thanks for any feedback on ongoing development in racks mgmt!