Refactoring on DROP/ALTER SET SCHEMA/ALTER RENAME TO statement

The series of attached patches try to have refactoring on several ddl
statements; that consolidates distributed routines for each object
types into a common routine to minimize the number of upcoming hooks
for external security.
Please apply the series of patches in order of part-1, part-2, part-3
then part-4.

Part-1) DROP statement refactoring
It is a remaining portion of what I submitted in the last commit fest.
It allows object types that didn't used DropStmt in gram.y to go
through RemoveObjects(), instead of individual RemoveXXXX().

Part-2) Groundworks on objectaddress.c
This patch adds necessary groundworks for Part-3 and Part-4.
It adds ObjectPropertyType of objectaddress.c index-oid and cache-id
for name lookup and attribute number of object name; these field is
used to detect namespace conflict on object_exists_namespace() that
shall be called on refactored ALTER SET SCHEMA/RENAME TO.
It also reduce some arguments of check_object_ownership(), and allows
to call this function without knowledge of ObjectType and text
representation. It allows to check ownership using this function from
the code path of AlterObjectNamespace_oid() that does not have (or
need to look up catalog to obtain) ObjectType information.
In addition, it adds regression test cases for ALTER SET SCHEMA/RENAME TO.

Part-3) ALTER SET SCHEMA statement refactoring
This patch refactoring routines of ALTER SET SCHEMA implementations of
most object types; except for relations, types and extensions. This
portion was originally designed to use a common routine
(AlterObjectNamespace) via wrapper function that delivers
characteristic properties of object types, then this design was
replaced by facilities of objectaddress.c.

Part-4) ALTER RENAME TO statement refactoring
This patch refactoring routines of ALTER RENAME TO implementation of
most object types; except for databases, relations, columns, triggers
and roles.

Thanks,
-- 
KaiGai Kohei <kaigai@kaigai.gr.jp>