refactor(AFieldset): rework title look and support custom tags

src/components/generic/AFieldset.vue

 <template>
-  <component :is="as" class="tw-shadow tw-p-6 tw-rounded tw-m-0">
+  <component :is="as" class="tw-shadow tw-rounded tw-m-0">
     <template v-if="title">
       <component
-        :is="as === 'fieldset' ? 'legend' : 'h2'"
-        class="tw-text-xl tw-font-bold -tw-mt-2 tw-m-0 tw-mb-3"
+        :is="titleTag ? titleTag : as === 'fieldset' ? 'legend' : 'h2'"
+        class="tw-font-bold tw-m-0 tw-px-6 tw-py-3 tw-border-b tw-border-gray-200 tw-w-full"
         :class="{ 'tw-float-left tw-w-full': as === 'fieldset' }"
         >{{ title }}</component
       >
       <div v-if="as === 'fieldset'" class="tw-clear-left" role="presentation" />
     </template>
 
-    <slot />
+    <div class="tw-p-6">
+      <slot />
+    </div>
   </component>
 </template>
 
@@ -19,10 +21,12 @@ withDefaults(
   defineProps<{
     title?: string
     as?: string
+    titleTag?: string | undefined
   }>(),
   {
     as: 'fieldset',
     title: '',
+    titleTag: undefined,
   },
 )
 </script>