Move map configuration into config file

[jamiefolsom]

• Mapbox endpoints, credentials could be in the config file
• MEL Catalog endpoints could be in the config file
• Navigation and pages could be built from a manifest fetched from MEL Catalog

[jamiefolsom]

See comments on this PR: https://github.com/hofstra/itinerary/pull/2/files/cc0cf7c93f590f5e5b79ec6afcb8f4c8aeb72bea#diff-d333e891a781fb9543f9f049b766a2fbR36