Develop a blocking quic server to use for the writing of a guide

[nhorman]

Simmilar to demos/guide/tls-server-block.c, we need a quic-server-block application

Note, this is just a task for writing the code, not the documentation

### Tasks
- [ ] Review tls-server-block
- [ ] Review quic-client-block
- [ ] Implement a quic-server-block application that uses the quic api to respond to quic connections