Enhancement: Allow custom scripts for custom placeholders

[estruyf]

To further enhance the placeholders that can be used in the content types. It would be good to investigate if it would be possible to have a custom script capability.

[estruyf]

Testing out with the following implementation:

{
  "frontMatter.taxonomy.contentTypes": [
    {
      "name": "test",
      "pageBundle": false,
      "fields": [
        {
          "title": "Title",
          "name": "title",
          "type": "string"
        },
        {
          "title": "Unique ID",
          "name": "uniqueId",
          "type": "string",
          "default": "{{uniqueId}}"
        },
      ]
    }
  ],
  "frontMatter.content.placeholders": [
    {
      "id": "uniqueId",
      "script": "./scripts/uniqueId.js",
      "command": "~/.nvm/versions/node/v16.13.1/bin/node"
    }
  ]
}

The script gets two arguments:

1. File path
2. Title of the document

const arguments = process.argv;

if (arguments && arguments.length > 0) {
  const workspaceArg = arguments[2];
  const filePath = arguments[3];
  const title = arguments[4];

  console.log(Math.random().toString(36).substring(2, 15));
}

The outcome of the newly generated file its front matter:

[estruyf]

Another test with a known placeholder from Front Matter:

{
  "frontMatter.taxonomy.contentTypes": [
    {
      "name": "test",
      "pageBundle": false,
      "fields": [
        {
          "title": "Title",
          "name": "title",
          "type": "string"
        },
        {
          "title": "Random",
          "name": "random",
          "type": "string",
          "default": "{{uniqueId}}-{{slug}}"
        },
      ]
    }
  ]
}

[estruyf]

• Added a new notification message when the content is being created. This is useful when some placeholders take up some time to process. Example: creating a social image on the fly.
• Added the workspace path as the first argument.
• Added a notification when the custom placeholder failed to process.