Refactor of state committing

[FabijanC]

Usage related changes

• None

Development related changes

• Titular refactor:
  • Remove redundant CommittedClassStorage::insert_and_commit
  • Call commit_with_diff directly on Starknet instead of on pending_state
    • Reduce visibility of StarknetState::commit_with_diff to pub crate
  • Rename generate_new_block to generate_new_block_and_state to better reflect its functionality
  • Created while implementing the proposal in Memory exhaustion  #272 (comment)
  • Not enough improvement to c l o s e issue: Refactor state #484

Checklist:

• Checked out the contribution guidelines
• Applied formatting - ./scripts/format.sh
• No linter errors - ./scripts/clippy_check.sh
• No unused dependencies - ./scripts/check_unused_deps.sh
• No spelling errors - ./scripts/check_spelling.sh
• Performed code self-review
• Rebased to the latest commit of the target branch (or merged it into my branch)
• Updated the docs if needed - ./website/README.md
• Linked the issues resolvable by this PR - linking info
• Updated the tests if needed; all passing - execution info