AVM: Add bn256 pairing opcodes experimentally

[jannotti]

Cleanups to allow merge of experimental pairing opcodes

Some doc tweaks, and moved implementation to pairing.go

These opcodes should stay in vFuture until

1. We consider the deserialization format
2. We have unit tests
3. We consider BLS 12-381 (and the opcodes of eip 2537)
4. Audit of gnark-crypto library

[jannotti]

@bo-abstrlabs please have a look to confirm nothing you care about has changed.

[ahangsu]

seems langspec is conflicting with the doc.go?

nvm, seems we are updated with new commits...

[jannotti]

seems langspec is conflicting with the doc.go?

nvm, seems we are updated with new commits...

ninja force push

[codecov]

Codecov Report

Merging #4013 (847e0a9) into master (b3e19e7) will decrease coverage by 0.03%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #4013      +/-   ##
==========================================
- Coverage   54.46%   54.42%   -0.04%     
==========================================
  Files         390      391       +1     
  Lines       48513    48570      +57     
==========================================
+ Hits        26421    26433      +12     
- Misses      19868    19915      +47     
+ Partials     2224     2222       -2     

Impacted Files	Coverage Δ
data/transactions/logic/doc.go	60.00% <ø> (ø)
data/transactions/logic/opcodes.go	84.86% <ø> (ø)
data/transactions/logic/pairing.go	0.00% <0.00%> (ø)
cmd/algoh/blockWatcher.go	77.77% <0.00%> (-3.18%)	⬇️
data/abi/abi_type.go	87.67% <0.00%> (-0.95%)	⬇️
ledger/acctupdates.go	68.77% <0.00%> (-0.66%)	⬇️
catchup/service.go	69.62% <0.00%> (+0.24%)	⬆️
network/wsPeer.go	68.88% <0.00%> (+0.83%)	⬆️
data/transactions/verify/txn.go	45.02% <0.00%> (+0.86%)	⬆️
util/metrics/counter.go	88.50% <0.00%> (+2.29%)	⬆️
... and 3 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b3e19e7...847e0a9. Read the comment docs.

[ahangsu]

seems like most of the changes are actually in go-mod/go-sum, while the others are simply from #3655, looks good to me

[bo-abstrlabs]

@jannotti Thanks. Looks good to me!