Add custom header parameter to all module

Add custom header parameter based on @clinta work
in netbox-community#1327

Author: benoit-ferre

changelogs/fragments/add-custom-headers.yml

@@ -0,0 +1,2 @@
+minor-changes:
+  - Add support for custom headers for all modules

plugins/doc_fragments/common.py

@@ -50,4 +50,8 @@ class ModuleDocFragment(object):
       - Certificate path
     required: false
     type: raw
+  headers:
+    description: Dictionary of headers to be passed to the NetBox API.
+    required: false
+    type: dict
 """

plugins/module_utils/netbox_utils.py

@@ -723,6 +723,7 @@
     query_params=dict(required=False, type="list", elements="str"),
     validate_certs=dict(type="raw", default=True),
     cert=dict(type="raw", required=False),
+    headers=dict(type="dict", required=False),
 )
 
 
@@ -751,6 +752,10 @@ def __init__(self, module, endpoint, nb_client=None):
         token = self.module.params["netbox_token"]
         ssl_verify = self.module.params["validate_certs"]
         cert = self.module.params["cert"]
+        headers = self.module.params["netbox_url"]
+
+        if isinstance(headers, str):
+            headers = json.loads(headers)
 
         # Attempt to initiate connection to NetBox
         if nb_client is None:
@@ -807,6 +812,7 @@ def _version_check_greater(self, greater, lesser, greater_or_equal=False):
     def _connect_netbox_api(self, url, token, ssl_verify, cert):
         try:
             session = requests.Session()
+            session.headers = headers
             session.verify = ssl_verify
             if cert:
                 session.cert = tuple(i for i in cert)