provide generic way(s) to select taxonomic lineages on sourmash commands

[ctb]

starting from discussion here,

Simple use case: I know the family of my organism and just want to get genbank/gtdb matches to anything in that family.

and here:

When we do this, it would be really neat to allow signature selection on the taxonomy, e.g. --include s__Phaeobacter. Yes, we can currently do this with sig grep or picklists using the taxonomy file, but seamless integration would be great.

I wrote:

This doesn't belong in sourmash tax which is specific to taxonomy manipulations - where this really belongs is somewhere generic to all the other sourmash subcommands,as with picklists and --include/--exclude. We want the rest of sourmash to "understand" taxonomies when they are present.

and this then connects with other metadata ideas e.g. stuff in #2180 and #1916.

[ctb]

this could easily be done with standalone manifests - see #1916.