fix!: Use module imports for icons

[mayank99]

Build tested working fine (including tree shaking) with:

• Vite 3 (uses esbuild/rollup)
• Next.js 12 (uses webpack 5)
• CRA 5 (uses webpack 5)
• CRA 4 (uses webpack 4)

Astro (which uses vite SSR) still has problems building, even when i added export maps to icon packages. Investigating.