Resize Month Events and Resize Week/Day Events on Both Ends (#578)

* Fix incorrect destructuring of eventComponent in DayColumn#renderEvents

* Pass through an event component with a resize anchor

* Make resize anchor draggable

* Make resize anchor droppable

* Use isOver prop to resize

* Rename and refactor

* Correct alignment of entire anchor and not just icon

* Differentiate between drag and drop callback fires

* Add example code for using the resizable event feature

* Rename ResizableEventComponent -> ResizableEvent

* Pass Down Resizable Prop to Event Cell

Summary: For <EventCell /> to know that it can be resized I am passing down the resize prop to that component. This is because, unlike in the previous implementation, I am not passing down what would be the eventWrapper from the dragAndDrop addon. I didn't know how to pass down multiple components based on whether the calendar was resizable. So I went this route. Sorry, not sorry.

* Update Resize Function and Rename Component

Summary: Updated the resize function to be aware of the end as well as the start time. This is when there are two dnd handlers on an event at once.

I renamed the component to be more semantic with its usage. Styles were correspondingly updated.

* Add Top Drag and Refactor Component

Summary: Refactored <ResizableEvent /> and added the ability to resize the top component.

* Refactor If/Else Statement

Summary: Refactored the if/else statement into a switch statement.

* feat: pass down event components from top-level

summary: remove resizable prop from lower-level components so that resizable logic is encapsulated in the dnd addon.

* Pass 'isAllDay' prop to header event components

* docs: update docs with resizable prop

.github/ISSUE_TEMPLATE.md

@@ -1,4 +1,4 @@
-#### Do you want to request a *feature* or report a *bug*?
+#### Do you want to request a _feature_ or report a _bug_?
 
 #### What's the current behavior?