METAR API and MongoDB Updates

[jlefkoff]

This PR contains the following changes:

• Corrected the middleware API calls to the VATSIM METAR service as well as the AWC for SGIMETs.
• Added CORS support in preparation for running on a separate web server.
• Added importer code for RW AxR adaptation data.
• Updated requirements.txt
• Added a mongoDB compose file

[CrazyKidJack]

Will merge but I did create issue #8