add overview of used voice assistant aliases

[Mariusthvdb]

been looking for a useful voice assistant alias on an entity, and kept getting the wrong response... turns out, my new alias wasnt as new as I had thought, and the other entity was targeted...

Hence I started looking for an overview, only to find out we dont have that yet.

So, this FR is simple:
Please consider adding an overview/search option where we can test if a new Alias is in fact new, or unique enough.

During the same search I found that we can add the same alias to very different entities, which seems a bug....

the overview would be a first step to prevent those situations.

thanks for considering