Benchmarks: fix scoping issue with crypto modules
Context
This MR renames the module Signature of lib_benchmark to Algebraic_signature and makes the appropriate changes where it is used.
This allows to open Tezos_crypto without its module Signature being shadowed.
This MR is in preparation of !5444 (merged) which introduces different signature versions in the shell.
Manually testing the MR
No change in functionality, check CI.
Edited by Alain Mebsout