Add definitions to Guide

[amilan17]

we discussed adding the ICAO definition for aeronautical meteorology to the Guide and I just realized that there is no such section.

[amilan17]

@Haddouch101 @6a6d74

[golfvert]

Jeremy wrote something. It has to be integrated in the document.

[6a6d74]

@golfvert - what I wrote for aeronautical meteorology (ie, WIS2-SWIM interoperability) is already in the Guide. @amilan17 - I can't remember the specifics of the definition(s) we talked about. Please can you elaborate? Thanks.

[amilan17]

@6a6d74 I think there was a request to provide an official definition of 'aeronautical meteorology' and I was expecting to find a definitions section in the guide... I suggest that it's to add later