[enhancement] Add custom filters / folders

[neitsa]

I don't know if this request falls into the goals of HaystackContinued, but did you considered at some point to add custom filters or even "folders" for different vessels?

E.g. I have a fleet of probes for long distance communication (remotetech mod) and i'd like to keep them all under the same directory. Is it possible to do this with HaystackContinued? If no would you consider to add this feature or maybe a pull request for it?

Thanks a lot :)