Extract server discovery and shared room discovery / creation into utility function

[ulope]

Abstract

Sub-issue from #3243.
In the initial implementation the MS needs to be able to join a fully federated global room to receive balance proofs from Raiden clients.
Extract the server discovery / login mechanism and discovery room creation mechanism from the MatrixTransport into a utility function, this will provide a temporary solution to the MS until #3252 is implemented and the full MatrixTransport can be used by the MS.

Tasks

• Extract server discovery, login
• Extract shared room creation

Time estimation

1 Week

[andrevmatos]

I think creation of the room should be quite easy, but this issue must also track filter receiving/sending logic for these special rooms, since all send/receive logic holds certain assumptions about p2p architecture (e.g. send_async expects a peer address, receiving messages filters by invited-by peers). In this case, raiden transport should only send, not care about receiving, but some care must be put on this part as well

[Dominik1999]

Thanks for creating that issue. We, the MS / PFS team, will prepare everything to include this. We would need that temporary solution working until 01.02.2019. Do you think this is possible?