Child chain mintable predicates E2E tests

[Stefan-Ethernal]

Description

This PR tweaks CLI commands for sending bridge transactions and implements E2E tests which prove that child chain mintable predicates are working correctly.
Note that child chain mintable native token is mapped only on mintable predicates (it is prevented to be mapped in non-mintable ones).

Bridge CLI commands UX changes

Bridge deposit commands have a new flag called --minter-key, which represents the private key of the account that is able to do token minting (e.g. has associated MINTER_ROLE etc.). If it is provided, deposit command is going to mint tokens to the sender account (otherwise it would do just deposit).

All bridge commands are enhanced with an additional flag called --child-chain-mintable. This flag denotes whether child chain mintable predicates are engaged in a given bridge transaction. It is used to determine whether exit events (aka L2StateSynced events) are extracted from a receipt. Depending on the direction of assets bridging, exit events can be present either:

• for withdrawals when using non-child chain mintable predicates
• for deposits when using child chain mintable predicates

Mandatory stake-token flag to rootchain deploy command

Introduced mandatory stake-token flag to rootchain deploy command, because the previous approach was not correct, since instead of using root chain native token, we were using child chain native token root chain pairing address.

E2E tests

Implemented two e2e tests, which are bridging child chain-originated tokens (mintable native tokens and ERC721 tokens).

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually