Refactor TranscriptManager to requester needs #28
Description
Currently the TranscriptManager is only designed for responder needs (missing functionality for M2).
The TranscriptContext has to be altered to also include a M2 variant (maybe renaming TranscriptContext::M1 to M and adding documentation is enough).
Likewise the fields, documentation and methods of the TranscriptManager have to be adjusted to reflect this.
(TODO: Check if the responder always only deals with M1 and the requester only with M2)