Adjust contribute menu and change homepage announcement

[robroboto]

1. Add MoveIt Workshop to the "Contribute" menu of moveit.ros.org
   -Use text "MoveIt Workshop"
   -List above "World MoveIt Day"
   -Links to https://moveit.ros.org/moveit/ros/2019/09/19/moveit-workshop-macau.html

2. Replace the MoveIt homepage announcement (currently about World MoveIt Day) with an announcement about the MoveIt Workshop.
   -Use the text "First annual MoveIt Workshop is November 2!
   -Add link to https://moveit.ros.org/moveit/ros/2019/09/19/moveit-workshop-macau.html

[robroboto]

@JafarAbdi

[v4hn]

Replace the MoveIt homepage announcement (currently about World MoveIt Day) with an announcement about the MoveIt Workshop

World MoveIt Day is (theoretically) relevant to everyone visiting the page, whereas the workshop is only interesting for people attending IROS/ROSCon.
I would prefer to keep WMD on the page, although you could add it as a second announcement I guess?

[robroboto]

True, but the announcement banner is for relevant MoveIt events. We've had World MoveIt Day as the announcement for quite some time now, along with blog posts, LinkedIn, Twitter, etc since July/August. Plus chronologically, the MoveIt workshop is approaching sooner (Nov 2), so is more relevant in that sense.

I was thinking to have the MoveIt workshop as the announcement for now and switch it back to World MoveIt Day when it's closer to time (since it's on Nov 20).

I'm helping organize both events for MoveIt, so definitely want to promote both events, just trying to find a (marketing) balance.