[Firo]: Support exchange address

[w20089527]

Description

A new address for exchange requirement.

As exchange address has same unlocking script with regular address(p2pkh), our work will involve as following:

1. Support derive of this address
2. Support validation of this address
3. Support this address as an output which added a new instruction OP_EXCHANGEADDR

FYI: as we do not have any config in registry.json for this kind of address, I defined a ExchangeAddress with constants that only works for mainnet, if want to support testnet or regtest, we need to define corresponding class for them.

Check here for exchange address description:
https://github.com/firoorg/firo/wiki/Exchange-Addresses

Here is the detail pr for exchange address:
firoorg/firo#1356

How to test

Testcases added for this feature

Types of changes

New feature (non-breaking change which adds functionality)

Checklist

• Create pull request as draft initially, unless its complete.
• Add tests to cover changes as needed.
• Update documentation as needed.
• If there is a related Issue, mention it in the description.

If you're adding a new blockchain

• I have read the guidelines for adding a new blockchain.

[satoshiotomakan]

Hi @w20089527, thank you for opening the PR!

[satoshiotomakan]

Thank you for the fix! LGTM
I have one suggestion in case if you need to support testnet addresses