List custom tab resources

Retrieve the documents, knowledge base entries and subprocessors that a custom tab can reference, for populating the tab editor before anything is created.

curl -X GET "https://example.com/api/v1/custom-tabs/new"

{  "resources": {    "documents": [      {}    ],    "knowledgeBase": [      {}    ],    "subprocessors": [      {}    ]  }}