feat(service): Add workplace chat

[ainsleyclark]

Is your feature request related to a problem? Please describe.
N/A

Describe the solution you'd like
It would be great to support Workplace by Facebook. I'm not sure if this is in tandem with the ticket open re supporting Facebook. But I'm pretty sure the Workplace API allows the sending of messages very easily.

Many thanks.

Describe alternatives you've considered
N/A

Additional context
https://developers.facebook.com/docs/workplace/bots/

[nikoksr]

@ainsleyclark thanks for bringing this up. Didn't know about Facebook Workplace until now.

[nguyenvanduocit]

Maybe I will contribute this provider, I have some project on that.

[mrhillsman]

I would like to contribute this implementation could I be assigned?

[ainsleyclark]

@mrhillsman I have created a package for WP, dropping it in for reference:

https://github.com/ainsleyclark/workplace

[mrhillsman]

Just a quick update that I am still working on the implementation, thank you @ainsleyclark for the reference material, some of it was used and I added you as a contributor to the README.md; I hope that is sufficient. I picked this up as a part of Hacktoberfest.