Move cli options definitions to piptools.scripts.options module

[atugushev]

pip-compile and pip-sync both have common options, so this change reduces duplication and ensures the options are consistent.

[theryanwalker]

Great! At least the descriptions are now synced:

Before:

$ pip-compile --help | grep -A 1 -- --index-url
  -i, --index-url TEXT            Change index URL (defaults to
                                  https://pypi.org/simple)
                                  
$ pip-sync --help | grep  -- --index-url
  -i, --index-url TEXT      Change index URL (defaults to PyPI)

After:

$ pip-compile --help | grep -A 1 -- --index-url
  -i, --index-url TEXT            Change index URL (defaults to
                                  https://pypi.org/simple)

$ pip-sync --help | grep -A 1 -- --index-url
  -i, --index-url TEXT      Change index URL (defaults to
                            https://pypi.org/simple)

[atugushev]

Thanks @theryanwalker!