Add Season 8 pubkeys and update hardfork constants

[smk762]

Harvested from https://docs.google.com/spreadsheets/d/1qcRn6YF_UdjeSJxSz80nS1cqpqS-5x0NnGKo9VJPPq8/edit?usp=sharing

Related dPoW PR at KomodoPlatform/dPoW#563

[DeckerSU]

These changes should go directly into the patch-s8-prepare branch, and then it should be merged with dev. The patch-s8-prepare branch already has everything needed, including constants, etc. The main purpose of this branch is to have a state where we only need to replace the pubkeys.

[DeckerSU]

Conflicts have been resolved here. To finalize the changes in dev, we need to approve the following:

1. PR Remove libsnark, libgmp, mini-gmp #613 (patch-remove-libsnark -> dev)
2. PR build: use native clang as darwin compiler #618 (patch-macos-build-clang -> patch-remove-libsnark)
3. PR fix datacarrier related command-line args #619 (patch-data-carrier -> dev)
4. PR Add Season 8 pubkeys and update hardfork constants #620 (add/s8-pubkeys -> patch-s8-prepare, which already contains patch-remove-libsnark, patch-macos-build-clang, and KIP0002 + KIP0003 changes)

Afterward, we need to create a final PR to merge the remaining changes into dev, with final checks. I can handle the merge and resolve any potential conflicts myself, but I'll need the reviewers' approval of PRs (1)-(4) first.

[ca333]

current estimation for height 4125988 is October 1st

cc @DeckerSU @smk762

[smk762]

Ideally this should be (re)calculated as late as possible to make it as accurate as possible wrt to recent/anticipated block production rate.

[ca333]

ok, will recalc tonight and include in #623

[DeckerSU]

I created my own script for these calculations, which you can find here: estimate-blocks.py. According to my calculations, we have the following:

- Average blocks per day: 1370.96
- Minimum blocks per day: 1260
- Maximum blocks per day: 1457
- Current height: 4063104
- Days to future: 45
- Estimated block height at 2024-10-04 13:37:33: 4124797

Based on this, October 4th corresponds to approximately block 4124797 on average. Currently, we have 4125988 hardcoded, which should occur later than 2024-10-04 13:37:33. So, my guess is that 4125988 is okay.