Remove gobjectmodule

This finishes what was started in b2529624
and moves the remaining code mostly into gimodule.

While this makes the large file even larger, it's a good starting point
for more cleanups.
12 jobs for remove-gobjectmodule-plus-cleanup in 14 minutes and 11 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build And Test
passed python2.7 #16926

00:05:26

passed python2-mingw32 #16922
win32

00:01:48

passed python2-mingw64 #16923
win32

00:01:41

passed python3.4 #16927

00:03:16

passed python3.5 #16928

00:02:29

passed python3.6 #16929

00:02:53

passed python3.7 #16930

00:05:47

passed python3-mingw32 #16924
win32

00:01:38

passed python3-mingw64 #16925
win32

00:01:34

passed xenial-i386-py2 #16931

00:02:57

 
  Coverage
passed coverage #17029

00:01:54

failed coverage #16932

00:17:43