Expose functionality to only build a binary `.gp` codelet, without adding it to a graph

[giordano]

Currently we only provide the macro @codelet to build the .gp codelet and add it to a graph, but it was suggested that it can be useful to just compile the .gp file, outside of a specific program. We should then expose this functionality: we already do that under the hood, we only need to reorganise the code and the API to allow users to only get the .gp file.

[devin12422]

Hey, do you have any leads on this? I'm looking to make my own interface/library for the IPUs. I bought some second hand but I haven't set them up yet. Personally, I'm planning on rewriting the device drivers to log all calls and parameters once I've got them set up, and then I'll see where I can go from there. Maybe we can help each other out.