Adds bigip gtm monitor http module (#39944)

This module can be used to manage http monitors on a GTM

test/units/modules/network/f5/fixtures/load_gtm_monitor_http_1.json

@@ -0,0 +1,21 @@
+{
+    "kind": "tm:gtm:monitor:http:httpstate",
+    "name": "foo",
+    "partition": "Common",
+    "fullPath": "/Common/foo",
+    "generation": 0,
+    "selfLink": "https://localhost/mgmt/tm/gtm/monitor/http/~Common~foo?ver=13.1.0.4",
+    "defaultsFrom": "/Common/http",
+    "description": "my description",
+    "destination": "3.3.3.3:8080",
+    "ignoreDownResponse": "disabled",
+    "interval": 30,
+    "password": "secret",
+    "probeTimeout": 5,
+    "recv": "the receive string",
+    "reverse": "enabled",
+    "send": "GET /",
+    "timeout": 120,
+    "transparent": "enabled",
+    "username": "user1"
+}