Improve adding inheritance functionality

Problem/Motivation

Adding inheritance form allow a user to select a source role and a target role which is working well, however this can be very annoying if you are dealing with hundreds of subgroups. In my case I have 155 parents and children in my tree and at least two roles for each group type, I need inheritances some from top to low and the opposite for some cases so I realize developing code to facilitate this will take less time than trying to do this with the current Add inheritance form.

I attached the current form and the one I proposed in a custom module.

Steps to reproduce

See the add inheritance form under subgroup settings.

Proposed resolution

I propose to improve the form by select one source role and multiple target roles so you can reduce a lot of time when doing this configuration.

Remaining tasks

Decide either we improve the existing form or we add a new contrib module for this work.

User interface changes

Change the add inheritance or add a new menu for a smart add inheritance.

API changes

Data model changes