[RUNTIME] Major code cleanup (#711)

This PR does the following:
- CUDA utilities (e.g., cuGetInfo) won't be compiled as part of libtriton.so anymore.
- Refactoring driver/llvm.cc to split it between PTX codegen and python.
- By extension this will also deprecate include/external so Triton won't have to live with a copy of some CUDA/Hip headers anymore.
- `triton-translate` becomes a `triton.tools.aot` Python utility that re-uses functions from the triton.compile sub-module.

lib/CMakeLists.txt

@@ -1,5 +1,4 @@
 # add_subdirectory(codegen)
-add_subdirectory(driver)
 add_subdirectory(Analysis)
 add_subdirectory(Conversion)
 add_subdirectory(Dialect)