make holiday stops flow responsive

[twrichards]

This PR encompasses all the changes to make the holiday stop flow introduced in #227 responsive across different devices in accordance with the wireframes/designs provided.

Notes

There are a few additional changes and refactors to bring about the responsiveness screenshotted further down...

• improved breakpoint calculation (and introduced height based breakpoints)
• improved mechanism for wrapping text on long buttons on small viewports
• added 401 handling for calls to holiday-stop-api in alignment with the way AsyncLoader handles these scenarios (e.g. when the user tries to select some holiday dates, but the users session has gone over one hour, then redirect to reauthenticate)
• two further tweaks/hacks had to be made in the wrapping of onefinestay/react-daterange-picker to achieve an 'infinite' scroll type experience
  • because the library has a touchStart handler when presenting many calendars stacked (as we do now for mobile) this was causing dates to be selected while scrolling, this was fixed by adding onTouchStartCapture={e => e.stopPropagation()} on the parent container, which catches the event on the way down to the child component (solved by understanding the capture/target/bubbling lifecycle of events - see https://javascript.info/bubbling-and-capturing#capturing)
  • when dates change, by default the library jumps the calendars in-order to ensure the selection is in view, which is problematic in the 'infinite' scroll mode, so this behaviour is suppressed by replacing the isStartOrEndVisible function with () => true when this.props.numberOfCalendars > 12
• some tweaks to the Modal component to ensure it is independently scrollable when the content is larger than the devices viewport

Holiday Overview Screen

mobile	tablet
	desktop

Holiday Date Chooser Screen

mobile NOTE: as user scrolls the date boxes and count of issues selected turns into a 'sticky' header as the user scrolls beyond it to the calendars
desktop	tablet

Holiday Review Screen

mobile	tablet
	desktop

Holiday Confirmation Screen

mobile	tablet
	desktop

[arausuy]

Reviewed at desks 👍 Thanks for the PR write up!

[prout-bot]

Seen on PROD (merged by @twrichards 4 minutes and 16 seconds ago) Please check your changes!