Add Bitcoin Gold implementation

[h4x3rotab]

Description

(Update since #911: fixed android and ios integration tests)

Bitcoin Gold is already added to the trustwallet/assets. This PR adds the implementation including the address codec and transaction signing logic.

Testing instructions

Passes unit tests: ./build/tests/tests tests
Create a new address in walletconsole:

> coin btg
Set active coin to: bitcoingold    Use 'coin' to change.  (name: 'bitcoin gold'  symbol: btg  numericalid: 156)
> addrDefault
Result:  btg1q8hnwn2j2vges5u9h9t456zfd46sjxfmxvk3rvl

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist

• Prefix PR title with [WIP] if necessary.
• Add tests to cover changes as needed.
• Update documentation as needed.
• If there is a related Issue, mention it in the description (e.g. 'Fixes Adopt Zilliqa to bech32 address format #444 ).

[h4x3rotab]

https://dev.azure.com/TrustWallet/Trust%20Wallet%20Core/_build/results?buildId=26514&view=logs&j=275f1d19-1bd8-5591-b06b-07d489ea915a&t=40b1ee41-44d6-5bba-aa04-4b76a5c732e5&l=14

docker: Error response from daemon: pull access denied for trustwallet/wallet-core, repository does not exist or may require 'docker login': denied: requested access to the resource is denied.

Maybe flaky CI errors?

[codecov]

Codecov Report

Merging #926 into master will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #926      +/-   ##
==========================================
+ Coverage   93.30%   93.37%   +0.06%     
==========================================
  Files         418      424       +6     
  Lines       12167    12384     +217     
==========================================
+ Hits        11353    11564     +211     
- Misses        814      820       +6     

Impacted Files	Coverage Δ
src/Bitcoin/Entry.cpp	100.00% <ø> (ø)
src/Bitcoin/Entry.h	100.00% <ø> (ø)
src/interface/TWData.cpp	74.57% <0.00%> (-1.79%)	⬇️
src/Coin.cpp	98.13% <0.00%> (-0.46%)	⬇️
src/XXHash64.h	95.41% <0.00%> (-0.43%)	⬇️
src/Elrond/Address.cpp	100.00% <0.00%> (ø)
src/Elrond/Address.h	100.00% <0.00%> (ø)
src/Elrond/Entry.cpp	100.00% <0.00%> (ø)
src/Elrond/Entry.h	100.00% <0.00%> (ø)
src/Elrond/Signer.cpp	100.00% <0.00%> (ø)
... and 3 more

---

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[hewigovens]

Hi, We have no plan to add BTG (or other bitcoin forks) to Trust Wallet

[optout21]

The iOS CI build failed with this error:

Testing failed:
	Type 'CoinType' has no member 'bitcoingold'
	Testing cancelled because the build failed.

Maybe BitcoinGold?

[optout21]

The Linux CI build failure is infrastructure-related, we will check.

[h4x3rotab]

Hi, We have no plan to add BTG (or other bitcoin forks) to Trust Wallet

Hi @hewigovens, yeah, we fully understood that. We checked the integration guidance and our first thought was that merging it into wallet-core could benefit more projects and the open source blockchain space, even given TrustWallet is not going to add it. Btw would you mind introduce us the go-to person for a chat? We would really appreciate it.

[hewigovens]

Missing lock script / zpub tests:

https://developer.trustwallet.com/wallet-core/newblockchain#bitcoin-forks-checklist

[optout21]

/azp run

[h4x3rotab]

Missing lock script / zpub tests:

https://developer.trustwallet.com/wallet-core/newblockchain#bitcoin-forks-checklist

Added at 11aa44f. Please take a look :)

New Blockchain Support

[hewigovens]

please rebase master, Android CI should be fixed

[h4x3rotab]

Looks like we are ready to go :)