Freakble

- Add project classifiers
- Add more commands autocompetion
- Ensure we always use a write-with-response.

Add support for MacOS, thanks to Giuseppe Marco Randazzo.

- Rewrote the Bluetooth LE stuff to direcly use bleak library.
- BREAKING CHAGES: the CLI flag to set Bluetooth LE timeout is renamed from
`--ble-connection-timeout` into `--timeout`.
- Import GUI stuff inside the `gui` command so that if Python is installed
without `tk` other commands would work.

Fix theme installation command in README.

Make GUI themes installable from pipx/pip.

Make GUI theming optional.