Loader: Configure "default groups" in the Loader

[BigRoy]

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

In the Loader you can click CTRL+G to create a custom grouping for the selected subsets. In Avalon you could define custom groups that appear by default in the create group popup, in the form of adding this to project[config] in the database:

        "groups" : [ 
            {
                "name" : "Deprecated",
                "icon" : "trash",
                "color" : "grey"
            }
        ],

OpenPype does not have any tools in place to add these nor customize this.

Describe the solution you'd like

The OpenPype Admin Settings should allow to define these per project and make sure the tools can pick those up.

Describe alternatives you've considered

Adding the data directly into the database, but I rather don't want to.

Additional Context

The custom groups would appear when clicking on the button to the right which can show with a custom icon and will show additional to the Groups existing on the currently selected asset's subsets.

OpenPype without default groups defined:

Avalon with default groups defined:

We used this previously to easily mark soms subsets as "dont load these' in the Loader.

[cuID:OP-2627]