feat(wfe-server-protos): add gRPC service definitions for workflow server

13 RPCs in wfe.v1.Wfe service: RegisterWorkflow, StartWorkflow,
GetWorkflow, CancelWorkflow, SuspendWorkflow, ResumeWorkflow,
SearchWorkflows, PublishEvent, WatchLifecycle (stream),
StreamLogs (stream), SearchLogs, ListDefinitions.

wfe-server-protos/build.rs

@@ -0,0 +1,17 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let proto_files = vec!["proto/wfe/v1/wfe.proto"];
+
+    let mut prost_config = prost_build::Config::new();
+    prost_config.include_file("mod.rs");
+
+    tonic_prost_build::configure()
+        .build_server(true)
+        .build_client(true)
+        .compile_with_config(
+            prost_config,
+            &proto_files,
+            &["proto"],
+        )?;
+
+    Ok(())
+}