Call info frame equivalent for signaling in account info

Adds an additional tab in the Account Info frame with an editor pane in which any additional information can be displayed. This can be seen as the equivalent of the call info frame but for chat/signaling information.
This patch also adds information to the pane with the remote server address and TLS information (if used), including a link to view the certificate.
The pane offers an easy way for anybody to add additional information before finding a more permanent first-class place in the GUI or to use it for more advanced information rarely needed by normal users etc.

(Replaces the previous pull request with same title as I screwed up this Git thing again...)