Strip out old code

All of these files have been moved to either:

- https://github.com/sigp/lighthouse-beacon
- https://github.com/sigp/lighthouse-validator
- https://github.com/sigp/lighthouse-common

For rationale, see: https://github.com/sigp/lighthouse/issues/197

protos/src/lib.rs

@@ -1,5 +0,0 @@
-// The protobuf code-generator is not up-to-date with clippy, therefore we silence some warnings.
-#[allow(renamed_and_removed_lints)]
-pub mod services;
-#[allow(renamed_and_removed_lints)]
-pub mod services_grpc;