[FRONTEND] Refactor file hierarchy (#1464)

The purpose of this PR is to remove some circular dependencies and
separate concerns better in the frontend. It's still not perfect --
`triton.compile` still includes a few runtime architecture-specific
component, but at least much better than before.

This PR still assumes that AMD only supports empty kernels right now.
Other PRs will follow to make the frontend supports multiple devices in
a more modular way.

bin/triton-translate.cpp

@@ -121,8 +121,8 @@ LogicalResult tritonTranslateMain(int argc, char **argv,
   }
 
   llvm::LLVMContext llvmContext;
-  auto llvmir =
-      translateTritonGPUToLLVMIR(&llvmContext, *module, SMArch.getValue());
+  auto llvmir = translateTritonGPUToLLVMIR(&llvmContext, *module,
+                                           SMArch.getValue(), false /*isRocm*/);
   if (!llvmir) {
     llvm::errs() << "Translate to LLVM IR failed";
   }