Add interactive room link to pm command

[ZenKyma]

Hello! It would be neat to directly receive room link from the bridge the moment you open a chat with the pm command for example: Created portal room with <number> at <room link> and invited you to it.
Just like when you type in the command a second time and the bridge answers with "You already have a private chat portal with <number> at <room link>".

Is there any interest in implementing this feature? I opened a corresponding pull request in #598.