Add Mattermost Connector and its documentation

[bibich]

Hi there!
Here is a proposition for a Mattermost connector.
It's quite basic for now and it's my first contribution to tock, so do not hesitate to tell me what's wrong.

[Benvii]

Thanks @bibich for this contribution, see my review comments.

About the documentation a huge refactoring was done and some files have moved to different location but it should be easy to report your changes.
I suggestion you start with a rebasing then report your changes to the moved files.

Do you think a demo of this connector could be done during one the Tock Virtual Coffee (I see you are already in the invite), we could also help you about the remain todos (for instance reply on the original channel could be done using metadata to keep the channelID..).

[bibich]

@Benvii Thanks for your detailed review.

I've resolved all issues you reported. Sorry for the delay.
Let me know if it's ok for you now.

Do you think a demo of this connector could be done during one the Tock Virtual Coffee (I see you are already in the invite), we could also help you about the remain todos (for instance reply on the original channel could be done using metadata to keep the channelID..).

Sure. But I'm not sure to be available this week, but the next one it will be fine.

[Benvii]

Thanks for the updates and the fixes @bibich 🙂, sorry for the late approval