rpc rewrite: control RPCs using gRPC + separate RPC for data transfer

transport/ssh: update go-netssh to new version
    => supports CloseWrite and Deadlines
    => build: require Go 1.11 (netssh requires it)

rpc/dataconn/timeoutconn/internal/wireevaluator/testbed/README.md

@@ -0,0 +1,15 @@
+This directory contains very hacky test automation for wireevaluator based on nested Ansible playbooks.
+
+* Copy `inventory.example` to `inventory`
+* Adjust `inventory` IP addresses as needed
+* Make sure there's an OpenSSH server running on the serve host
+* Make sure there's no firewalling whatsoever between the hosts
+* Run `GENKEYS=1 ./gen_files.sh` to re-generate self-signed TLS certs
+* Run the following command, adjusting the `wireevaluator_repeat` value to the number of times you want to repeat each test
+
+```
+ansible-playbook -i inventory all.yml -e `wireevaluator_repeat=3`
+```
+
+Generally, things are fine if the playbook doesn't show any panics from wireevaluator.
+