The purpose of the preprocessor is to load a model with the TFLM interpreter, allocate tensors, and then capture the resulting data structures. To capture this data, we need to provide structure and serialization to it for ingesting into the code generator. This commit defines a preprocessor data schema with generated C++ and python bindings for it. Unfortunately, we need to check-in the generated code, as the Makefiles are currently not capable of running the flatc compiler. An update script is included to help keep these files in sync.
BUG=b/295076067
