Implement new UI component for icons #230

- Introduce `AppIcon.vue`, offering improved performance over the
  previous `fort-awesome` dependency. This implementation reduces bundle
  size by 67.31KB (tested for web using `npm run build -- --mode prod`).
- Migrate Font Awesome 5 icons to Font Awesome 6.

This commit facilitates migration to Vue 3.0 (#230) and ensures no Vue
component remains tightly bound to a specific Vue version, enhancing
code portability.

Font Awesome license is not included because Font Awesome revokes its
right:

> "Attribution is no longer required as of Font Awesome 3.0"
>
> Sources:
>
> - https://fontawesome.com/v4/license/ (archived: https://web.archive.org/web/20231003213441/https://fontawesome.com/v4/license/, https://archive.ph/Yy9j5)
> - https://github.com/FortAwesome/Font-Awesome/wiki (archived: https://web.archive.org/web/20231003214646/https://github.com/FortAwesome/Font-Awesome/wiki, https://archive.ph/C6sXv)

This commit removes following third-party production dependencies:

- `@fortawesome/vue-fontawesome`
- `@fortawesome/free-solid-svg-icons`
- `@fortawesome/free-regular-svg-icons`
- `@fortawesome/free-brands-svg-icons`
- `@fortawesome/fontawesome-svg-core`

src/presentation/components/Shared/Icon/UseSvgLoader.ts

@@ -0,0 +1,92 @@
+import {
+  WatchSource, readonly, ref, watch,
+} from 'vue';
+import { AsyncLazy } from '@/infrastructure/Threading/AsyncLazy';
+import { IconName } from './IconName';
+
+export function useSvgLoader(
+  iconWatcher: WatchSource<IconName>,
+  loaders: FileLoaders = RawSvgLoaders,
+) {
+  const svgContent = ref<string>('');
+
+  watch(iconWatcher, async (iconName) => {
+    svgContent.value = await lazyLoadSvg(iconName, loaders);
+  }, { immediate: true });
+
+  return {
+    svgContent: readonly(svgContent),
+  };
+}
+
+export function clearIconCache() {
+  LazyIconCache.clear();
+}
+
+export type FileLoaders = Record<string, () => Promise<string>>;
+
+const LazyIconCache = new Map<IconName, AsyncLazy<string>>();
+
+async function lazyLoadSvg(name: IconName, loaders: FileLoaders): Promise<string> {
+  let iconLoader = LazyIconCache.get(name);
+  if (!iconLoader) {
+    iconLoader = new AsyncLazy<string>(() => loadSvg(name, loaders));
+    LazyIconCache.set(name, iconLoader);
+  }
+  const icon = await iconLoader.getValue();
+  return icon;
+}
+
+async function loadSvg(name: IconName, loaders: FileLoaders): Promise<string> {
+  const iconPath = `/assets/icons/${name}.svg`;
+  const loader = loaders[iconPath];
+  if (!loader) {
+    throw new Error(`missing icon for "${name}" in "${iconPath}"`);
+  }
+  const svgContent = await loader();
+  const modifiedContent = modifySvg(svgContent);
+  return modifiedContent;
+}
+
+const RawSvgLoaders = import.meta.glob('@/presentation/assets/icons/**/*.svg', {
+  as: 'raw', // This will load the SVG file content as a string.
+  /*
+    Using `eager: true` to preload all icons.
+    Pros:
+      - Speed: Icons are instantly accessible post-initial load.
+    Cons:
+      - Increased initial load time due to preloading of all icons.
+      - Increased bundle size.
+  */
+  eager: false,
+});
+
+function modifySvg(svgSource: string): string {
+  const parser = new DOMParser();
+  const doc = parser.parseFromString(svgSource, 'image/svg+xml');
+  let svgRoot = doc.documentElement;
+  svgRoot = removeSvgComments(svgRoot);
+  svgRoot = fillSvgCurrentColor(svgRoot);
+  return new XMLSerializer()
+    .serializeToString(svgRoot);
+}
+
+function removeSvgComments(svgRoot: HTMLElement): HTMLElement {
+  const comments = Array.from(svgRoot.childNodes).filter(
+    (node) => node.nodeType === Node.COMMENT_NODE,
+  );
+  for (const comment of comments) {
+    svgRoot.removeChild(comment);
+  }
+  Array.from(svgRoot.children).forEach((child) => {
+    removeSvgComments(child as HTMLElement);
+  });
+  return svgRoot;
+}
+
+function fillSvgCurrentColor(svgRoot: HTMLElement): HTMLElement {
+  svgRoot.querySelectorAll('path').forEach((el: Element) => {
+    el.setAttribute('fill', 'currentColor');
+  });
+  return svgRoot;
+}