feat: integrate schema.org support and enhance component structure

- Added schema.org support by introducing `schema-dts` for structured data in components.
- Updated `Head`, `BaseLayout`, and various page components to accept and utilize schema props for better SEO.
- Created new utility schemas for blog posts and website to standardize structured data implementation.
- Enhanced the `SocialLinks` section by utilizing dedicated icon components for improved maintainability.
- Refactored the `Header` component to improve accessibility and structure.
- Introduced new icons for social links and integrated them into the layout.

src/components/Icons/Email.astro

@@ -0,0 +1,20 @@
+<style lang="scss">
+	@use "../../scss/variables" as *;
+
+	a {
+		color: $colorText;
+		display: inline-block;
+		margin: 0 0.5rem;
+	}
+
+	svg {
+		vertical-align: middle;
+	}
+</style>
+
+<a href="mailto:valentin@popov.link" title="E-Mail" target="_blank">
+	<svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-label="E-Mail">
+		<path d="M4 4h16c1.1 0 2 .9 2 2v12c0 1.1-.9 2-2 2H4c-1.1 0-2-.9-2-2V6c0-1.1.9-2 2-2z"></path>
+		<polyline points="22,6 12,13 2,6"></polyline>
+	</svg>
+</a>