Use a pinia store to manage session state

Replace the convoluted useAccountSession composable with a pinia store
that in addition allows for the consolidation of all session related
functions to grouped into one module.

components/LogOutButton.vue

@@ -1,19 +1,7 @@
 <template>
-	<button type="button" @click="logOut">Log out</button>
+	<button type="button" @click="sessionStore.logOut">Log out</button>
 </template>
 
 <script setup lang="ts">
-const { refresh: sessionRefresh } = useAccountSession();
-
-async function logOut() {
-	try {
-		await $fetch.raw("/api/auth/session", {
-			method: "DELETE",
-		});
-		await sessionRefresh();
-
-	} catch (err: any) {
-		alert(`Log out failed: ${err.statusCode} ${err.statusMessage}`);
-	}
-}
+const sessionStore = useSessionStore();
 </script>