* Get PKcols inside tables - done with SQL for tables and with an additional step in Haskell for views. This fixes an fk column being considered as a pk column on views and corrects the test added on https://github.com/PostgREST/postgrest/pull/1875/files/1d549768580310e18aac4ffa6dbd01c5b77934a7#r853674126 * classify view key dependencies in SQL * remove Column from Relationship * Merge cols/fcols in Relationship and ensure allM2ORels and allViewsKeyDependencies fk columns are ordered - done by attnum in SQL * Cardinality now contains relColumns instead of Relationship - this simplifies getJoinConditions.