install biplist and pycountry by default on macOS

* biplist is only used for Apple iOS IPA files.
* pycountry is only used for linting countryCodes in mirror configs.

Both of these are included via the Debian packaging, where those packages
and updates are more vetted.  Homebrew for macOS makes it very difficult to
include optional dependencies, so this includes the optional dependencies
via distutils' method.

setup.py

@@ -93,6 +93,8 @@ setup(
         'platformdirs',
         'androguard >= 3.3.5',
         'asn1crypto',
+        # TODO use biplist on all platforms once IPA support is stable
+        'biplist ; sys_platform=="darwin"',
         'clint',
         'defusedxml',
         'GitPython',
@@ -101,6 +103,7 @@ setup(
         'Pillow',
         'apache-libcloud >= 0.14.1',
         'puremagic',
+        'pycountry ; sys_platform=="darwin"',
         'python-vagrant',
         'PyYAML',
         'qrcode',