Refactoring of `get_pids*` functions

hive/db/schema.py

hive/db/sql_scripts/condenser_get_by_account_comments.sql

hive/db/sql_scripts/condenser_get_by_blog_without_reblog.sql

hive/db/sql_scripts/condenser_get_by_feed_with_reblog.sql

hive/db/sql_scripts/condenser_get_by_replies_to_account.sql

hive/server/bridge_api/cursor.py

hive/server/bridge_api/methods.py

hive/server/bridge_api/objects.py

hive/server/condenser_api/cursor.py

hive/server/condenser_api/get_state.py

hive/server/condenser_api/methods.py

hive/server/condenser_api/objects.py

hive/server/hive_api/public.py

tests/tests_api