feature/cli

See merge request !2

monorepo:
- Completely rewrite README
- Rename `audio_demo.py` to `audio-demo.py`
- Update `audio-demo.py` to use `voluxcli` commands instead of running script in monorepo
- Moved `audio_demo.py` and `basic_demo.py` scripts into `voluxcli` package
- Add `enable-bash-completions.sh` script for enabling shell completion when `voluxcli` package is installed
- Replace `volux` package's `setup.py` with `pyproject.toml` for monorepo development (each package within the monorepo now has it's own `pyproject.toml` for building, publishing and using poetry commands.

volux:
- Add `open_counter` attribute to `TimedThresholdGate` that tracks number of calls it's been open for
- Add `get_sine` util for generating sine waves
- Add `__version__.py` so `voluxcli` can detect `volux`'s version
- Add `VoluxDemo` superclass for creating demos with
- Add simple README

voluxcli:
- Create new `voluxcli` package
- Add `basic` and `audio` demos originally from monorepo
- Add new `hue` demo
- Add simple README

voluxexamplemodule:
- Add simple README