adds provider argument to ios shared module

New argument `provider` added to the ios shared module that provides
the ability to pass all of the common ios arguments as a dict.  This commit
includes some minor bugfixes and refactoring of names.   It also includes
udpates to the ios documentation fragment for the new argument

lib/ansible/utils/module_docs_fragments/ios.py

@@ -63,5 +63,12 @@ options:
         does nothing
     required: false
     default: none
+  provider:
+    description:
+      - Convience method that allows all M(ios) arguments to be passed as
+        a dict object.  All constraints (required, choices, etc) must be
+        met either by individual arguments or values in this dict.
+    required: false
+    default: null
 
 """