feat(strapi5): add new provider with formats

[ThiloHettmer]

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

With strapi 5 the url for responsive images has changed.

Strapi 5 now prefixes responsive images with "thumbnail_", "small_" and so on.

Additionally Strapi 5 won't create images for a certain breakpoint if the source image has a lower resolution than the breakpoint.

Strapi does return on the image request a "formats" object which contains all generated image (partial) urls.

This change will add a new provider "strapi5" with the following functionality:

• Generates the correct image urls depending on the parameter modifiers.breakpoint (same parameter as before)
• Accepts optional modifiers.formats and will pick the correct url for the provided breakpoint. If there is no image for the breakpoint it will return the next available image with a lower resolution.
• Accepts optional modifiers.breakpoints to add custom breakpoints.

Example

const image = {
  url: 'test.jpg',
  formats: {
    thumbnail: {
      name: 'thumbnail_test.jpg',
      url: '/uploads/thumbnail_test.jpg',
    },
    small: {
      name: 'small_test.jpg',
      url: '/uploads/small_test.jpg',
    },
    medium: {
      name: 'medium_test.jpg',
      url: '/uploads/medium_test.jpg',
    },
    large: {
      name: 'large_test.jpg',
      url: '/uploads/large_test.jpg',
    },
  },
}

...

<NuxtImg :src="image.url" :modifiers={ breakpoint: 'medium', formats: image.formats } provider="strapi5" />

This is my first contribution ever, so please don't go hard on me ;)