Refactor crate into multiple subcrates

Cargo.lock

@@ -478,6 +478,10 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "protos"
+version = "0.1.0"
+
 [[package]]
 name = "quote"
 version = "1.0.45"
@@ -537,15 +541,30 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
 
 [[package]]
-name = "roto"
+name = "roto-benches"
 version = "0.1.0"
 dependencies = [
  "clap",
  "criterion",
  "env_logger",
  "log",
+ "roto-runtime",
 ]
 
+[[package]]
+name = "roto-codegen"
+version = "0.1.0"
+dependencies = [
+ "clap",
+ "env_logger",
+ "log",
+ "roto-runtime",
+]
+
+[[package]]
+name = "roto-runtime"
+version = "0.1.0"
+
 [[package]]
 name = "rustversion"
 version = "1.0.22"