Add an option to create a 1st party plugin

[alschmiedt]

Category

Plugins Component dev-tools

Is your feature request related to a problem? Please describe. When releasing there are certain fields that need to be filled out properly. In the past filling out these fields improperly has caused problems during a release.

Describe the solution you'd like We would like the dev-create script to allow us to specify that we want to create a first party plugin.

Something like:

npx @blockly/create-package my-plugin --type plugin --first-party

When creating a first party plugin we would:

• Precede the plugin name with '@blockly/'
• Fill out the publishConfig field with

    "publishConfig": {
        "access": "public",
        "registry": "https://wombat-dressing-room.appspot.com"
    },

• Fill out the homepage field
• Fill out the repository field
• Possibly add the plugin to the gh-pages index.md

Describe alternatives you've considered

Additional context