Trim data feeds to work with *24-hour cache* data.

[petersilva]

the original starting feed is UNIDATA, which is at least one (perhaps more) orders of magnitude data than what is on the GTS. to do a test for performance as a 24 cache, it makes sense to start with the actual data set, and not one far, far bigger. First shot at filtering is to just pick certain GTS type messages from within the WMO_Sketch_2mqtt.conf feed:

subtopic *.GTS.*.SA.#
subtopic *.GTS.*.SM.#
subtopic *.GTS.*.IS.#
subtopic *.GTS.*.FT.#

It would be great to get a full listing of the TT's needed to get a complete 24 hour cache.