add husky commit hooks to do housekeeping

[konnov]

This PR add husky commit hooks to do the following on git commit:

• check that eslint passes
• update the license boilerplate, that is, add the license header to the source files
• once we have Add prettier and the CI check #22 merged, it will also reformat the code.

This is all done, so we don't have to wait for Github actions to fail on these housekeeping tests.