Add package p5-astro-spacetrack

[trwyant]

This new package wraps the Perl Astro-SpaceTrack distribution, which downloads satellite orbital elements from the Space Track web site, as well as others. These would be used by satellite prediction programs such as p5-astro-satpass.

This is my initial package submission, and I was not sure what to put in the 'author' field. I seem to recall 'openmaintainer' being popular in the ones I spot checked, but since I do not have a commit bit, maybe 'nomaintainer' would be better. Please feel free to make the change yourself if you see fit, or to contact me and have me resubmit.

Thank you very much,

Tom Wyamt (mailing address to the contrary notwithstanding)