ENH: Convert team syncs from issues to slack only

[choldgraf]

This converts our team sync process to use the Slack Geekbot instead of GitHub issues each week. Here are major changes:

• Archives our actions and issue template around creating a weekly team sync. I've decided to archive them rather than delete them for now, in case we want to re-visit this practice. But I've added notes to delete them in a few months if we don't change things up.
• Moves our weekly sync process into the development coordination guide, since I think that's a more natural place for it.

ref #259

[GeorgianaElena]

This looks good to me.
Two small things I noticed though:

• the bot doesn't send the messages in the morning
• should we give more details about the Slack updates? I noticed there isn't any info about the M-W-F workflow. But maybe this would make sense in the TODO section.

[choldgraf]

@GeorgianaElena could you go into more detail on your second point? What extra information did you have in mind, and where? I'm happy to add in some extra detail somewhere!

[damianavila]

LGTM

[choldgraf]

Another ping for @GeorgianaElena to provide some guidance on what you mean by "give more details about the Slack updates". I'm happy to make changes if you wish, just not sure where you'd like them to be! If you don't think it's a blocker or don't have time to look by tomorrow, I'll merge this one in and we can always iterate

[GeorgianaElena]

should we give more details about the Slack updates? I noticed there isn't any info about the M-W-F workflow. But maybe this would make sense in the TODO section.

@choldgraf, sorry for my message being confusing 🤦 When I said "more details" I was referring to mentioning that the updates happen M-W-F. Definitely not a must or a blocker.

Sorry for the confusion again!

[choldgraf]

Ah thanks for that clarification @GeorgianaElena - I've added a sentence to convey this information as well! Will merge now :-)