Added onInit and useInitialized hooks

packages/svelte/src/lib/components/CallOnMount/CallOnMount.svelte

@@ -0,0 +1,14 @@
+<script lang="ts">
+  import { onMount } from 'svelte';
+
+  let _onMount: (() => void) | undefined = undefined;
+  export { _onMount as onMount };
+
+  let _onDestroy: (() => void) | undefined = undefined;
+  export { _onDestroy as onDestroy };
+
+  onMount(() => {
+    _onMount?.();
+    return _onDestroy;
+  });
+</script>

packages/svelte/src/lib/components/CallOnMount/index.ts

@@ -0,0 +1 @@
+export { default as CallOnMount } from './CallOnMount.svelte';