Move server traits to a separate crate

Summary: This diff turns a `thrift_library` with `name = "foo"` into 4 Rust targets: `:foo-rust` (as before), `:foo-rust-types` (as before), `:foo-rust-clients` (as before), and `:foo-rust-services` (new).

Reviewed By: zertosh, shayne-fletcher

Differential Revision: D53166618

fbshipit-source-id: 6f94f7a70f70de928f7320b06e6d638cc6ac1206

shed/thrift_compiler/src/lib.rs

@@ -216,6 +216,7 @@ impl Config {
                     fs::remove_file(out.join("consts.rs"))?;
                     fs::remove_file(out.join("errors.rs"))?;
                     fs::remove_file(out.join("mock.rs"))?;
+                    fs::remove_file(out.join("server.rs"))?;
                     fs::remove_file(out.join("services.rs"))?;
                     fs::remove_file(out.join("types.rs"))?;
 
@@ -287,6 +288,7 @@ impl Config {
                         fs::remove_file(submod.join("consts.rs"))?;
                         fs::remove_file(submod.join("errors.rs"))?;
                         fs::remove_file(submod.join("mock.rs"))?;
+                        fs::remove_file(submod.join("server.rs"))?;
                         fs::remove_file(submod.join("services.rs"))?;
                         fs::remove_file(submod.join("types.rs"))?;