Add citus_schema_move() that can be used to move tenant tables within a distributed
schema to another node. The function has two variations as simple wrappers around
citus_move_shard_placement() and citus_move_shard_placement_with_nodeid() respectively.
They pick a shard that belongs to the given tenant schema and resolve the source node
that contain the shards under given tenant schema. Hence their signatures are quite
similar to underlying functions:
```sql
-- citus_schema_move(), using target node name and node port
CREATE OR REPLACE FUNCTION pg_catalog.citus_schema_move(
schema_id regnamespace,
target_node_name text,
target_node_port integer,
shard_transfer_mode citus.shard_transfer_mode default 'auto')
RETURNS void
LANGUAGE C STRICT
AS 'MODULE_PATHNAME', $$citus_schema_move$$;
-- citus_schema_move(), using target node id
CREATE OR REPLACE FUNCTION pg_catalog.citus_schema_move(
schema_id regnamespace,
target_node_id integer,
shard_transfer_mode citus.shard_transfer_mode default 'auto')
RETURNS void
LANGUAGE C STRICT
AS 'MODULE_PATHNAME', $$citus_schema_move_with_nodeid$$;
```
Onur Tirtir