[doc]  A lot of required data fields are optional in document

Description of problem:

When invoke API to create or update some resources,  a lot of data fields are required, but in official document, they are "optional".

Take "PUT /api/v1/organization/{orgname}/applications/{client_id}" as example,

The definition of the request body is

......
    "UpdateApp": {
      "type": "object",
      "description": "Description of an updated application.",
      "required": [
        "name",
        "redirect_uri",
        "application_uri"
      ],
      "properties": {
        "name": { 
........

But in document, "name","redirect_uri" and "application_uri" are all optional.

If miss these required fields in CLI, will get error message.

There are a lot of this kind of problem in official document, it is better to update the document.