properly handle entity list values

When posting a new entity, Instead of using `stringify-values` on all attributes,
diversify the approach so that documents and photos (that map to a
list in c*) are converted into a list of strings.
stringify list for notes as well

same as for documents and photos, notes map to a list in cassandra.
reuse stringify list functions for profiles
use contains? to check for attribute presence
fix contains? attributes order
update-stringified-lists now accepts a vector of selectors
use those vectors!
more idiomatic version of update-stringified-list
Merge pull request #19 from MastodonC/bug/handle_entity_lists

Bug/handle entity lists