Update libqmatrixclient and some consumers

• new "sustaining" libqmatrixclient (er .. Quotient) release wth improvements in SSO and reduction in crashes.

https://github.com/quotient-im/libQuotient/releases/tag/0.5.3
https://github.com/quotient-im/libQuotient/releases/tag/0.5.3.1

• chase a newer rc for quaternion (a technical-minded Matrix client)
• bump the requirements in Spectral

There is a newer Spectral release as well, but it seems to be
incompatible with this libQuotient -- needs CMake support that
libQuotient does not install.