DAL: move root constants type into lib_crypto_dal and environment

The following discussion from !5996 (merged) should be addressed:

• @Saroupille started a discussion: (+2 comments)

  A suggestion which requires a bit of work, but IMHO, would be better.

  Since those constants are shared by the protocol and the shell, it would be better to have this type declaration in lib_crypto_dal directly. Then export this type to the environment (as well as its encoding). In particular, the make function could take this datatype as input.

  Then having the constant_parametric_constants using this datatype (you could use merge_objs to stay compatible). Otherwise, I think it is a bit odd as it is.