docs: Add instructions for local license header checks

[mileticveljko]

This PR updates the README.md to include instructions for managing license headers within the efc project:

• Added a section explaining the use of Hawkeye for license checks;
• Provided a check command to identify files missing headers locally;
• Provided a format command to automatically apply headers to incorrect files.

[DNedic]

Would it be possible to do this in pre-commit instead of users having to manually run it locally?

[filipembedded]

Good idea. We could definitely save some time with pre-commit checks. > Would it be possible to do this in pre-commit instead of users having to manually run it locally?

[filipembedded]

Good job