Add support for IN comparison for lists

[avaleske]

Steps:

• Merge solution to main
• merge upstream

For neighborhoods, unit size, and other filter types, we'll want to allow users to select multiple options of the same filter (for example, units with 1 and 2 bedrooms)

Right now the filter system assumes everything should be ANDed together, but queries like this need to be ORed together.

One option is to interpret a param with comma-separated values as a list, and use IN . So a querystring like ?filter[$comparison]=IN&filter[field]=val1,val2,val3 would come in as

{
  $comparison: "IN",
  field: val1,val2,val3,
}

which would be added to the query with a clause like AND WHERE lower(field) IN [val1, val2, val3]

This doesn't make as much sense if the comparison is something other than `IN but I think that's ok.

Also note the lowercasing of the field, which we'll do to the user provided values as well so the query is case-insensitive.

Also, while we're here, we should update the way the where params are inserted so that we're only inserting allowed strings

[avaleske]

Just waiting for the upstream PR to be merged:
bloom-housing#1634