Allow to have signatures (like email signatures)

[ohager]

Is your feature request related to a problem? Please describe. With the rise of 3rd party aliases, e.g. Unstoppable and Handshake, people can connect their Signum addresses to domain like names. When sending to other users accounts these aliases (and also the native aliases) are not visible for the receiver. Having them attached as message to tx could help to make aliases known to other users.

Describe the solution you'd like Under Account Management it should be possible to add/edit a short email like signature which will be automatically (or on selection via check box in senders menu) attached to a transactions body.