Feature: Update astro-icon to v1 and svgo

[Ticolyle]

Hello! My compliments to an excellent astro starter repo with great baseline accessibility.

When I first tried out this repo I ran into issues with svgo and it's dependency sharp.

While troubleshooting the build, I found that astro-icon had been updated to v1 with some breaking changes. After updating in my personal project I found the changes to be fairly straightforward and thought to replicate for you on the main repo.

Most of the changes needed are documented in the astro-icon upgrade docs: https://www.astroicon.dev/guides/upgrade/v1/

I also needed to make some minor changes to the css styles to match the current site design. These changes are needed as the astro-icon now delivers icons with the width and height props, not previously present on the svg elements.

package.json changes:

- upgrade astro-icon 0.7.3 => 1.0.2
- upgrade svgo 2.8.0 => 3.2.0
- add @iconify-json/ion
- add @iconify-json/mdi

Cheers, and let me know if you have any questions.

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[markteekman]

Hey @Ticolyle! Thanks for taking the time to upgrade Astro Icon on this repository, I always appreciate the help 😊 Your explanation is clear and the changes you've made look solid! Theres only one small issue, the Accessible Astro Components package still references to [astro-icon]. I'll fix that first and then merge your PR 😄 Thanks again!