Add mesh workshop details to program

[dcwalk]

We have two mesh workshops slotted in on the Friday:

• Jillian, NYC mesh
• Grant, People's Open

Let's get those up on the program!

• [x] email presenters
• [x] add blocks of time
• [x] add in descriptions

[dcwalk]

This should be resolved in https://github.com/ournetworks/ournetworks.ca/pull/134