feat: admin upload controls

[kendelljoseph]

What?

Adds the ability to add additional components to the file upload component.

export const Media: CollectionConfig = {
  slug: 'media',
  upload: {
    admin: {
      components: {
        controls: [
          '/collections/components/Control/index.js#CustomControl',
        ],
      },
    },
  },
  fields: [],
}

Why?

To enable the ability to add custom components when uploading documents near the primary upload operations.

[rilrom]

This makes me very happy. I'll no longer need a custom upload component for my image search plugin, thank you!

[PatrikKozak]

@kendelljoseph Can we update the styling of the Select a file & Paste url buttons or / it's parent wrappers so that the buttons do not stretch (like shown in your image above) if the parent height changes due to the custom components?

[kendelljoseph]

@PatrikKozak yep, will do!