feat(NewCharButton): Update NewCharButton

* Refactor NewCharButton
  * Remove BarIcon at NewCharButton
  * Replaced BaseRoundedButton and SVG

src/lib/UI/BaseRoundedButton.svelte

@@ -0,0 +1,16 @@
+<script lang="ts">
+  export let isDisabled: boolean = false;
+  export let onClick: () => void;
+</script>
+
+<button
+  disabled={isDisabled}
+  on:click={onClick}
+  class="flex h-[56px] w-[56px] cursor-pointer select-none items-center justify-center
+   transition-colors rounded-full
+   border border-gray-500 text-gray-300
+   hover:border-gray-300 
+   {isDisabled ? '!cursor-not-allowed' : ''}"
+>
+  <slot />
+</button>