gmacros: Add g_autoqueue to automatically free queues

This works as g_auto(s)list already does, and allows to create queues that are
fully auto free'd on destruction.
9 jobs for more-auto-macros in 26 minutes and 38 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Build
passed #294934
cross-android_api21_arm64

00:05:10

passed #294935
cross-android_api28_arm64

00:05:09

passed #294936
cross-mingw64

00:05:25

passed #294932
debian-stable-x86_64

00:05:01

passed #294931
fedora-x86_64

00:11:58

passed #294933
G_DISABLE_ASSERT

00:09:27

passed #294937
win32
msys2-mingw32

00:09:38

passed #294938
win32
vs2017-x64

00:09:00

 
  Coverage
passed #294939
coverage

00:01:56

75.2%