MDN/Development/Meetings/Planning

Replaces our old MDN Planning meetings:

Max Time:	60m
Required Attendees	MDN devs
Optional Attendees	MDN stake-holders
Outcomes	Cards in the #mdndev week board

In the weekly planning we:

1. Open the #mdndev week board
2. List PTO/Holidays/Availability this week
3. Open the MDN engineering roadmap
   1. Determine this week's "big rock" actions for projects in the "Current" column
4. Review waffle flags
   1. Create "small pebble" actions for each flag to clean up