gkeys: Add key-search action

Add _list_search() sub function.
Add category output and grouping.
Fix arg as a list searching as well as seed values as a list.
Use recursion to get to single value searches.
Make nick search to be partial unless --exact specified.
Move main key_search code to SeedHandler class, it is much better suited to this class.
Add 1name subparser option for single name entries only
Add seen tracking in key_search to eliminate duplicates
Add --all option to key-search
If --all is specified, it filters out search results to match a seed for all criteria specified.