new environment

On this MR I introduce a new environment that can be used as a base to any environment modification.

• rename V1 to V0 to avoid confusion on encoding (https://gitlab.com/cryptiumlabs/tezos/-/merge_requests/69#note_297091555) and V2 to V1

• 732228af : add a new environment V2 (renamed V1), same as V1 (renamed V0).

• 58b39b48 : inject a dummy protocol with new env, verify that it has the correct environment then activate it

• 70d5b5a9 : proto-alpha now use new environment

also not included on this MR

• 0b642795 : an example of how protocol signature modification can be conducted. This example does not use the renamed environment nor the correct file due to the splitting of the file tezos_protocol_environment.