Support legacy apps displayed on iPhone X in letter box

[jmoody]

Motivation

This is a significant rewrite of the portion of the server that computes view hit points.

I moved touch-util-related code from LPTouchUtils to LPWebQuery when the only caller was in LPWebQuery. This will, I think, make identifying code paths easier.

Since this a significant rewrite, it behooves us to run more tests than usual to ensure nothing is broken.

Completes:

• LPServer can find touch coordinates on legacy apps displayed in Letter Box on iPhone X VSTS

Tests

• [x] iPhoneOnlyApp
  • [x] iPhone 6 form factor
  • [x] iPhone X form factor
  • [x] Test Cloud - Force completed (1 device pending for > 2 hours)
• [x] CalSmoke
  • [x] iPhone 6 form factor
  • [x] iPhone X form factor
  • [x] Test Cloud - failures are expected (caused by unrelated problems)
• [x] CalWebApp
  • [x] iPhone 6 form factor
  • [x] iPhone X form factor
  • [x] iPad Retina form factor
  • [x] iPad 9.7 form factor
  • [x] iPad 10.5 form factor
  • [x] iPad 12.9 form factor
  • [x] Test Cloud - 1 device out of 39 failed - page never loaded.

[jmoody]

@john7doe Ready for review.