Move all styles in the CCD (custom and default) to rely on custom styles

[majapw]

As I have started using the CustomizableCalendarDay (again, not recommended but a very specific way of doing a very specific thing), I have found an issue where custom styles always override default styles. So, if you happen to have a day that is both blocked by minimum nights and selected (which happens all the time for a selected-start day with a minimum nights value greater than 0), if you have customized the minimum nights but not the selection, the minimum nights styling will always win.

We do not want this.

By moving the default stylings out of the StyleSheet and into props as default values, we address this issue.

to: @ljharb @erin-doyle @gabergg @noratarano @airbnb/webinfra

[coveralls]

Coverage increased (+0.2%) to 86.65% when pulling 285033d on maja-move-default-CCD-styles-into-inline-styles into 2db60a8 on master.