wip/dendrite 0.5.0 NetBSD

Dendrite is a second-generation Matrix homeserver written in Go. It intends to provide an efficient, reliable and scalable alternative to Synapse:

• Efficient: A small memory footprint with better baseline performance than an out-of-the-box Synapse.
• Reliable: Implements the Matrix specification as written, using the same test suite as Synapse as well as a brand new Go test suite.
• Scalable: can run on multiple machines and eventually scale to massive homeserver deployments.