Forward address metadata from PFS route query in messages

[fredo]

Querying paths for mediated payments return also a dictionary called matrix_users which maps an address to its current online matrix user. These information needs to be passed along the route as mediators will only know available matrix users to forward them to.

The goal is to have a complete presence less raiden transport for now

matrix users need to be passed in the class RouteState and included in the created messages for LockedTransfers and all other messages necessary.

How does this behave for passing the secret back until the initiator and for unlocked transfers? Maybe let's make another issue for that.

[fredo]

closed in favor of #6851 and #6880