Add the ability to create nested Tags via parents

[clayrosenthal]

Adds the ability to specify a parent or parent-uuid when creating a tag, which then creates a nested tag underneath the specified parent tag.

ex:

sn add tag --title nested --parent root

which then shows:

sn get tag --title 'root,nested'
{
  "tags": [
    {
        "uuid": "62909229-17ec-4d01-ad6d-bec554ca73e8",
        "content": {
            "title": "nested",
            "references": [
                {
                    "uuid": "811a20f3-a130-41f8-9fdc-599c08379efe",
                    "content_type": "Tag",
                    "reference_type": "TagToParentTag"
                }
            ],
            "appData": {
                "org.standardnotes.sn": {
                    "client_updated_at": "2023-12-11T05:58:28.727Z",
                    "prefersPlainEditor": false,
                    "pinned": false
                }
            }
        },
        "content_type": "Tag",
        "created_at": "2023-12-11T05:58:28.727Z",
        "updated_at": "2023-12-11T05:58:29.265Z"
    },
    {
        "uuid": "811a20f3-a130-41f8-9fdc-599c08379efe",
        "content": {
            "title": "root",
            "references": null,
            "appData": {
                "org.standardnotes.sn": {
                    "client_updated_at": "2023-12-11T05:58:15.720Z",
                    "prefersPlainEditor": false,
                    "pinned": false
                }
            }
        },
        "content_type": "Tag",
        "created_at": "2023-12-11T05:58:15.720Z",
        "updated_at": "2023-12-11T05:58:16.387Z"
    }
]
}

Needs to be merged after related gosn PR

[jonhadfield]

Thanks. Will take a look tomorrow.