Autoadmin: Incorporate the autoadmin app

Incorporate the external django-autoadmin app as a core app
and convert it into a Mayan app. This change adds the new
settings: "COMMON_AUTOADMIN_EMAIL", "AUTOADMIN_PASSWORD", and
"AUTOADMIN_USERNAME".

Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>

mayan/settings/base.py

@@ -68,7 +68,6 @@ INSTALLED_APPS = (
     'django.contrib.staticfiles',
     # 3rd party
     'actstream',
-    'autoadmin',
     'colorful',
     'corsheaders',
     'djcelery',
@@ -84,6 +83,7 @@ INSTALLED_APPS = (
     # Base apps
     'mayan.apps.acls',
     'mayan.apps.authentication',
+    'mayan.apps.autoadmin',
     'mayan.apps.common',
     'mayan.apps.converter',
     'mayan.apps.django_gpg',