need to standardize dependency (and API re-exporting) patterns

[plebhash]

currently most of the roles crates import crates from protocols in a redundant way

ideally, crates like network_helpers_sv2 and roles_logic_sv2 should re-export all the needed items, and we should avoid redundant imports on roles

for example: a role shouldn't really need to declare codec_sv2 as an explicit dependency... that should be an explicit dependency for network_helpers_sv2, and if role needs some API from codec_sv2, network_helpers_sv2 should simply re-export it