Update Bitmark to Bitcoin source code v.27

This PR upgrades Bitmark to Bitcoin code from 27.x branch. Bitmark git fork history is now in sync with Bitcoin repo, so future upstream merge with bitcoin should be far easier. With this PR Bitmark gets a lot of important bug fixes and bitcoin improvements, including Segwit which enables the creation of the lightning network. Hopefully one day LN can be a bridge to trade coins between different chains.

What is left to be done:

double-check if some code is missing. I've copied Bitmark source code changes to Bitcoin since Bitcoin has changed significantly since version 9. I've used 0.9.7.4 bitmark source since it is the most used version.
fix failing tests. Some tests are now failing because chainparams and mining algorithms have changed. I fixed some but there is still work to do.
more testing. I did basic testing on linux and windows, like chain sync, reindex-chainstate, send, receive, mining, etc... But more testing is needed especially in merge mining and on Mac OSX which I didn't test.
there are still a lot of files with the name bitcoin in their name. I would advise not to rename them because this will break the git history with the bitcoin source code. If you still want to rename them, use git mv. This way git history is maintained in most cases.
new bitcoin features like segwit, taproot, bech addresses, etc... are currently disabled, and can be enabled with a future soft fork.

Known issues:

because of a bug 133, this updated bitmark version can't sync up with the bitmark network. To sync up with the bitmark network you'll need to connect to bitmark v.9.7 nodes with a bug fix applied or another synced-up bitmark v.27 nodes. To connect to such nodes add a line for each node connect=nodeip:nodeport in bitmark.conf.
to build on linux using gcc version has to be <= 10.5.0, otherwise, Lyra2rev2 hashing doesn't work correctly. Couldn't figure out why, it might be some gcc regression which they are famous for, or it can be something in bitmark code. Clang compiler does not have this issue.

:+1: Let's revive the development of this legendary OG coin. :+1:

project-bitmark / bitmark

Update Bitmark to Bitcoin source code v.27 #134