CMake: Default SKIP_POSTPROCESS_BUNDLE to ON

Building on macOS with a recent CMake version would result in the
following error:

CMake Error at Source/Core/MacUpdater/CMakeLists.txt:48 (add_custom_command):
  The following keywords are not supported when using
  add_custom_command(TARGET): DEPENDS

As it turns out, this form of `add_custom_command` does not accept
DEPENDS, but versions of CMake prior to 3.31 silently dropped it.

In LabelMap.cpp, the code is currently unused so I was unable to test it.

In WiiUtils.cpp, the magic value `1u` was replaced by the constant value `DiscIO::PARTITION_UPDATE`.

Some generators (like Unix Makefiles and Xcode) copy an app's Info.plist at configure time.
This causes a problem when we need to generate the Info.plist at build time, like how we
currently do it with ScmRevGen. Instead of generating the Info.plist directly in ScmRevGen,
provide an Info.plist without any version information to CMake at configure time, have
ScmRevGen generate a separate plist file with the version information at build time, and
then merge the two together to create the final Info.plist.

The domain "dolphinteam.com" is not under our control, so we shouldn't be using it.