Improve "Signature" in Onsite

Use case: when there are multiple teams/communities and if there's an agent that works on more than one communities, he should be able to set one signature that populates his name and product name automatically.

For example, I work on ChannelReply, and right now, I can only set my signature:

There should be an option to use "placeholders" that automatically detects that community name from the ticket. Agent should be able to choose their signature like this: