Updates in API documentation

We've added a bunch of new parameters and descriptions to our developer guides and references.

1. Added information about parameter List Message in webhooks in the Chats API.

"message":
{
    "id": "0371a0ff-b78a-4c7b-8538-a7d547e10692",
    "type": "text",
    "text": "Lead #15926745 Message text",
    "markup": {
        "list_message": {
            "header": "What type of service do you want to receive?",
            "body": "Please select one of the answer options from the menu by clicking the button below.",
            "footer": "Sincerely, Test Company",
            "button": "Services",
            "sections": [
                {
                    "title": "Available services",
                    "rows": [
                        {
                            "callback_data": "vG9ujre8N7",
                            "title": "Service 1",
                            "description": "Service 1 description"
                        }
                    ]
                }
            ]
        }
    }
}

2. Added tags_to_add and tags_to_delete keys to lead/contact/company creation and editing via API. You can pass tags to add and delete using the keys. These keys can be useful for avoiding collisions when multiple integrations can simultaneously change an entity.
3. Updated Permissions article: X-Context-User-ID header is introduced. Full access term is specified.
4. Updated Sources API article: added the wabaparameter. Updated the Webhooks API article: added a new type add_chat_template_review hook.
5. Added with parameter descriptions in API methods of stages. Added the ability to add stage descriptions in API methods for adding stages. Added the ability to add/edit/delete stage descriptions in API methods for editing stages.

"descriptions": [
      {
        "level": "newbie",
        "description": "Stage description"
      }
    ]

6. Added with parameters user_rank, amojo_id, uuid in API methods of users .
7. Added description of parameters that need to be passed when using reply_to in sending/importing messages in Chats API section. Added description of parameters that come in webhooks when replying to a message (reply_to).
8. Described call_responsible parameter in adding calls via API. Added call_responsible parameter for adding an incoming lead of sip type (call) via API.
9. Added description of using files from the File API in custom fields.
10. Added is_need_to_trigger_digital_pipeline parameter when [adding notes](Added is_need_to_trigger_digital_pipeline parameter when adding notes to the Notes API.) via API.
11. Added a list of available tag colors for leads. Tag color is now returned in leads.

12. Added _embedded[source][external_id] and _embedded[source][type] parameters to the methods for adding leads.