Create a "Guidelines" List for contributing to the Slack Workspace

[sk8forether]

@sk8forether suggested this idea. This idea was prompted by a Slack discussion about when and where is it appropriate to use things like @channel and such, and the inherent difficulties for neurodiverse folks when trying to navigate social norms. The suggestion would be that having a list of guidelines for expected behavior in this Slack workspace may empower people to contribute without accidentally being perceived as rude or inconsiderate (i.e. by pinging too many people). The guidelines could also include links to "how tos" on controlling notifications.

This would likely fit well on the Get Involved page on the website, so it may also be worth discussing with Outreach WG folks.

@exoticDFT also suggested that - in conjunction with adding this resource - we could limit the chat features (such as @channel) to only maintainers of the Slack workspace or channel to make it easier to not make mistakes. He also noted:

Of course, this is limiting/restricting people from doing certain things, so that might be counter-productive in another way. But worth adding to the discussion...