Move push notification setting to separate page

Set up a dedicated Account Setttings page to hold account specific
settings such as the push notifications.

components/Header.vue

@@ -11,6 +11,7 @@
 				{{ session.account.name || "anonymous" }}
 				(s:{{ session.id }} a:{{ session.account.id }}{{ session.push ? " push" : null }})
 				{{ session.account.type }}
+				<NuxtLink to="/account/settings">Settings</NuxtLink>
 				<button type="button" @click="logOut">Log out</button>
 			</template>
 			<template v-else>