Auto-generate contract Go bindings from ABI

[friofry]

Currently we store both go-bindings and abi files for contracts (like ERC721.go)
This can lead to inconsistencies. Instead, we should treat ABI as the source of truth and auto-generate Go bindings during make generate to reduce errors and duplication.

[igor-sirotin]

In general, I am on the side of not staging the generated files.

But during #5878 we decided with @alaibe to keep the contracts generated files, because:

1. They never change
2. I wasn't able to re-compile them with the lates abigen version, because the -sol flag was removed.

[friofry]

Then, what about storing only Go bindings without the ABI files? ABI bindings are duplicated in the generated files.

[friofry]

In general, I am on the side of not staging the generated files.

I think it's similar to test mocks

1. They never change

True for ABI. The minor thing: the future version of Go might be incompatible with what we generated, or it might produce annoying warnings. It'll require regeneration.

2. I wasn't able to re-compile them with the lates abigen version, because the -sol flag was removed.

these cmdline worked for me:
abigen --abi CryptoPunks.abi --pkg cryptopunks --type CryptoPunks --out cryptopunks.go

[igor-sirotin]

@friofry not that I have a strong opinion in this, just shared the context of previous decisions.
Wallet team knows better how we use contract generated files, I trust you guys on this 🙂