Partial translation of proto-alpha

About half of the files are compiling (but not the interpreter or translator). I added to the blacklist.txt files the ones that are missing. We should handle them in a later task. For now, the files for proto_alpha are in the folder Proto_A to avoid colliding with the existing Proto_alpha.

The environment definitions are factorized differently, with source definitions in the folder src/Environment/Structs and then included in environment files for each version. This follows a bit the organization in https://gitlab.com/tezos/tezos/-/tree/master/src/lib_protocol_environment/structs