feat: implement command line executable

[paddy74]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 90.90909% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
usajobsapi/cli.py	90.90%	2 Missing and 3 partials ⚠️

Files with missing lines	Coverage Δ
usajobsapi/cli.py	91.07% <90.90%> (+91.07%)	⬆️