Update validate-modules (#20932)

* Update validate-modules

* Validates ANSIBLE_METADATA
* Ensures imports happen after documentation vars
* Some pep8 cleanup

* Clean up some left over unneeded code

* Update modules for new module guidelines and validate-modules checks

* Update imports for ec2_vpc_route_table and ec2_vpc_nat_gateway

lib/ansible/modules/cloud/misc/xenserver_facts.py

@@ -32,15 +32,6 @@ author:
 options: {}
 '''
 
-import platform
-
-HAVE_XENAPI = False
-try:
-    import XenAPI
-    HAVE_XENAPI = True
-except ImportError:
-    pass
-
 EXAMPLES = '''
 - name: Gather facts from xenserver
    xenserver:
@@ -60,6 +51,16 @@ EXAMPLES = '''
 # }
 '''
 
+import platform
+
+HAVE_XENAPI = False
+try:
+    import XenAPI
+    HAVE_XENAPI = True
+except ImportError:
+    pass
+
+
 class XenServerFacts:
     def __init__(self):
         self.codes = {