Parse matrix links

https://spec.matrix.org/v1.2/appendices/#uris

• matrix: uri
• matrix.to link

Not stateful, so implement it as a separate class in libkazvclient.

• type(): room/user/event/...
• roomId()
• roomAlias()
• roomIdOrAlias()
• userId()
• eventId()
• static parse(): takes either matrix uri or matrix.to link
• toMatrixUri()
• toMatrixTo()