[webexteams] Initial contribution

Hi all,

I’m submitting a PR for a new binding that only exposes a new action to send messages over Cisco’s webex teams service.

Readme is here: openhab-addons/README.md at initial-webexteams · tdeckers/openhab-addons · GitHub

PR link: [webexteams] Initial contribution by tdeckers · Pull Request #13492 · openhab/openhab-addons · GitHub

Happy to take feedback.