improvement: Fixture generation split based on hive specificity

[spencer-tb]

This PR updates fixture generation such that it is split into 2 seperate formats. The format is determined by the --enable-hive flag:

1. The --disable-hive flag has been replaced by the --enable-hive flag. I decided to flip this due to increasing queries about the extra hive fields within the fixtures.
2. Without the --enable-hive flag, the default format is used. Client teams use this within there CI/CD.
3. With the --enable-hive an new fixture format is generated, similar to the current but only with the fields required by the hive pyspec simulator.
4. Its worth noting that we require feature: Add engine API forkchoice updated information in fixtures #256 to be merged first, which adds the forkchoice version information for the hive pyspec simulator.

Note: after we merge this PR we will have to start including 2 tar files within every new release. One for the default fixture format fixtures.tar.gz and another for the hive fixture format fixtures_hive.tar.gz.

[spencer-tb]

Tests for the hive fixture format have been added for reference, for any additional changes.

The hive fixture format is consumable in the pyspec simulator - tagging: ethereum/hive#844

These have been updated for both solc version 0.8.20 &0.8.21 to still account for padding differences.

[marioevz]

LGTM!

We can leave the fixture refactor for a follow up PR.