[ERC1155Handler] switch from mintBatch to mint interface

[axvn]

Description

Added ERC1155 support, this is built on the ERC20 data format 0x[tokenId][amount][addressLen][address], rather than using the batchMint data format.

Corresponding PR for the relayer: ChainSafe/chainbridge-core#289

How Has This Been Tested? Testing details.

Unit tests and integration tests provided.

Live demo can be tried out here: http://13.250.39.184:3001/ (bridge between Mumbai and Rinkeby), you can get test tokens from opensea testnet.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

Checklist:

• I have commented my code, particularly in hard-to-understand areas.
• I have ensured that all acceptance criteria (or expected behavior) from issue are met
• I have updated the documentation locally and in chainbridge-docs.
• I have added tests to cover my changes.
• I have ensured that all the checks are passing and green, I've signed the CLA bot

[CLAassistant]

All committers have signed the CLA.