Create 'cancel visits' page (admin side)

[philipmjohnson]

Create a page that enables OCCC staff to cancel scheduled visits (due to staff shortage or whatever).

This page should:

• List all scheduled visits for the next seven days.
• Provide a checkbox next to each visit to indicate if it should be canceled.
• For each visit, also provide a checkbox indicating if a text message notification should be sent.
• Provide a text field that OCCC staff can use to describe why the visit is being cancelled.
• Upon submission, the scheduled visits are removed, and text messages indicating that along with the explanation are sent out.