[AddonManager] separate the Macro class

Separate the Macro class of the AddonManager into addonmanager_macro.py
to prepare for future support for dependent files for macros from the
git repository.

src/Mod/AddonManager/addonmanager_utilities.py

@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+
+import os
+import sys
+if sys.version_info.major < 3:
+    import urllib2
+else:
+    import urllib.request as urllib2
+
+from PySide import QtGui
+
+# Qt tanslation handling
+try:
+    _encoding = QtGui.QApplication.UnicodeUTF8
+    def translate(context, text, disambig=None):
+        return QtGui.QApplication.translate(context, text, disambig, _encoding)
+except AttributeError:
+    def translate(context, text, disambig=None):
+        return QtGui.QApplication.translate(context, text, disambig)
+
+ssl_ctx = None
+try:
+    import ssl
+except ImportError:
+    pass
+else:
+    try:
+        ssl_ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
+    except AttributeError:
+        pass
+
+
+def urlopen(url):
+    """Opens an url with urllib2"""
+    if ssl_ctx:
+        u = urllib2.urlopen(url, context=ssl_ctx)
+    else:
+        u = urllib2.urlopen(url)
+    return u