Have extension packaging scripts (FROM unpackage) check objects ownership

[strk]

As per ​https://lists.osgeo.org/pipermail/postgis-devel/2020-February/028465.html if we want our packaging scripts to be safe we should check ownership of objects before adding them to our extension.

Objects not owned by a superuser should not be packaged.

[strk]

This was fixed upstream in PostgreSQL itself: ​https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=5579726bd60a6e7afb04a3548bced348cd5ffd89

[Sandro Santilli <strk@…>]

In 06f49e8/git:

Check ownership of functions match that of extension upon packaging

References #4648

[Sandro Santilli <strk@…>]

In af7d4657/git:

Check ownership of functions match that of extension upon packaging

References #4648 in 3.3 branch

[Sandro Santilli <strk@…>]

In fa756dd/git:

Check ownership of functions match that of extension upon packaging

References #4648 in 3.2 branch (3.2.4dev)

[Sandro Santilli <strk@…>]

In a8a9ec7c/git:

Add NEWS item about packaging checked ownership

References #4648 in 3.3 branch (3.3.2dev)

[Sandro Santilli <strk@…>]

In 3442f4d/git:

Check ownership of functions match that of extension upon packaging

References #4648 in 3.1 branch (3.1.8dev)

[Sandro Santilli <strk@…>]

In 6c1718af/git:

Check ownership of functions match that of extension upon packaging

References #4648 in 3.0 branch (3.0.8dev)

[Sandro Santilli <strk@…>]

In e2bf40c/git:

Set ownership of packaged functions to extension owner

Still check that the functions were owned by a superuser.

References #4648
References #5545
References #5566