Integrate VFPC Functionality

[TheoBearman]

As discussed on Slack, it would be great if we could integrate VFPC's functionality into UKCP. Perhaps we could pull info from sids.txt files from the UK sector file to create a version of VFPC's Sid.json file which covers all of the UK airfields included within it.

Additionally, we have information on level restrictions and engine-type restrictions attached to certain routes through the SRD. Weight restrictions on certain SIDs would probably have to be added to the UK wide Sid.json file manually though.

Thanks in advance!