fix: handle only image file extensions with the next image loader

[RyanClementsHax]

• make next image loader apply only to assets not being requested by css files
• handle css assets requested by css files by declaring them as assets
• handle css url and import resolution in the same way that nextjs does
• refactor examples to include custom font example
• refactor examples to have better layout
• refactor examples to have simpler css
• refactor examples to include nextjs version on each page for easier identification of what version of next is being used
• refactor examples to include serve command
• refactor examples to no longer include eslint as to simplify the examples
• refactor examples to be able to run next build and next start

fixes #15

[github-actions]

🎉 This PR is included in version 1.4.1 🎉

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