Reply support for Matrix

[vpzomtrrfrt]

Implements sending and receiving reply messages for Matrix bridges

In doing this, I moved the protocol stripping downstream from FindCanonicalMsgID since the previous behaviour made the ParentID value inconsistent

[42wim]

Thanks! could you fix the small linting issue, I'll try to do a review the coming week.

[codeclimate]

Code Climate has analyzed commit a0b2076 and detected 2 issues on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	2

View more on Code Climate.

[42wim]

Thanks! 🚀