Rewritten Spinners to easy add new spinners

[d-chris]

#30 (comment)

Description of new feature, or changes

1. rewritten Spinners to a wrapper which holds multiple Enums within a list. LegacySpinners still available.
2. load cli-spinners directly from json from submodule, for easy / lazy maintenance
3. allow the user to add new spinners easily, see examples\example2.py
4. using poetry instead of setuptools
5. pytest running with 100% coverage
6. check spinners for encoding, see examples\example1.py. intended to use within halo to allow ascii spinners for windows. maybe use instead of is_supported()

Checklist

• Your branch is up-to-date with the base branch
• You've included at least one test if this is a new feature
• All tests are passing

Related Issues and Discussions

#30

People to notify

@manrajgrover
@tpinniger