Introduce forking

[FabijanC]

Usage related changes

• Close Mainnet forking #18
• Introduce --fork-network <NETWORK>
  • Specify the sequencer API to be used for fallback calls, e.g. https://alpha4-2.starknet.io; can be:
    • Network name: alpha-goerli, alpha-goerli2, alpha-mainnet (maybe testnet and mainnet would be better choices)
    • Network URL, e.g. https://alpha4-2.starknet.io
• Introduce --fork-block <BLOCK_NUMBER>
  • Specify the block to be forked from (and to which all fallback calls will be done)
  • Defaults to latest (latest block number is fetched on forked-devnet startup and used throughout)
• Change fee token address to 0x49D36570D4E46F48E99674BD3FCC84644DDD6B96F7C741B1562B82F9E004DC7 (same as mainnet and testnet)
  • BREAKING
• Add cool yellow warnings.

Development related changes

• Reduce methods in Origin
• Remove special lite mode deployment (and corresponding classes):
  • Turns out the "lite" deployment was slower than normal deployment.
• Add gateway url specifier to some test functions (invoke, call, run_starknet) - needed to perform calls on fork origins.
• Add lint suppression to direct access of starknet.state.state.cache._class_hash_writes
• Fee token and udc test bodies are extracted so they can be imported to fork tests.
• Tests now depend on a third-party network: StarkNet's sequencer server, but only its feeder gateway, so no transactions are awaited and all requests ideally resolve instantly (simple GET requests).
• Suppress deprecation warnings in tests
• Suppress linting error about too many public methods in starknet_wrapper.py
• Add scripts that help local testing.
• Some methods had to become async (e.g. origin.py), which then propagated.
• Make some methods in test/util.py accept target URL (feeder_gateway_url).

Checklist:

• Applied formatting - ./scripts/format.sh
• No linter errors - ./scripts/lint.sh
• Performed code self-review
• Rebased to the last commit of the target branch (or merged it into my branch)
• Documented the changes
• Linked the issues which this PR resolves
• Updated the tests
• All tests are passing