Revamp "add sighting" modal

[norrisng-bc]

• Completely overhaul "add sighting" modal to only ask for:
  • Date range
  • (Sub)region
  • Moose count
• Sightings page has been updated to reflect
• Cleanup
  • Remove geolocation code
  • Cleanup other unused code and saga actions

Note: tick hair loss as an additional field has not been implemented yet, but it will be displayed in the sightings page once so.