Add method to get L1 message hash

[ddoktorski]

Closes #1139

Introduced changes

• Function to get L1 message hash for L1_Handler transactions

Some tests from tests_ci_on_network expected to fail at this point. It should be fixed once #1201 is merged.

• This PR contains breaking changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (6a63c74) 98.05% compared to head (ab884c8) 98.05%.

Additional details and impacted files

@@             Coverage Diff              @@
##           development    #1205   +/-   ##
============================================
  Coverage        98.05%   98.05%           
============================================
  Files               90       90           
  Lines             4719     4741   +22     
============================================
+ Hits              4627     4649   +22     
  Misses              92       92           

Files	Coverage Δ
starknet_py/hash/utils.py	100.00% <100.00%> (ø)
starknet_py/net/client_utils.py	100.00% <100.00%> (ø)
starknet_py/net/full_node_client.py	97.64% <100.00%> (+0.07%)	⬆️

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[tomek0123456789]

Looks good, just needs adding tests for the utils functions!

[ddoktorski]

Tests for keccak256 function taken from Solidity repository:

• https://github.com/ethereum/solidity/blob/develop/test/libsolidity/semanticTests/builtinFunctions/keccak256.sol
• https://github.com/ethereum/solidity/blob/develop/test/libsolutil/Keccak256.cpp

[tomek0123456789]

LGTM, great job!