Make everything surround the actual Zmanim page itself

[NightScript370]

Right now, the current site (elyahu41.github.io/royzmanim) has everything as separate pages. With the exclusion of the Molad calendars, I'd prefer handling the extra content as a modal rather than a separate page.

• Make Settings a Modal (Settings - Customization of the website #13)
• Make initial greetings a modal
• Make About a Modal
  • Accessible from the initial greetings
• Read location data from localStorage instead of URL prompts.