Ability to create a campaign from the calendar

[thepaulfox]

Describe the feature you'd like to request

As a marketing manager, I'd like to create campaigns from the calendar so I don't have to go to another tab to do it.

Describe the solution you'd like

Allow the user to click on a date or highlight a range of dates. After they do that, pop up a new campaign screen with the start and end date filled in.

https://fullcalendar.io/docs/date-clicking-selecting