UI: Rewrite web UI, add URL routing and components

See #156

server/ui-src/components/message/Headers.vue

@@ -0,0 +1,38 @@
+
+<script>
+import commonMixins from '../../mixins/CommonMixins'
+
+export default {
+    props: {
+        message: Object
+    },
+
+    mixins: [commonMixins],
+
+    data() {
+        return {
+            headers: false
+        }
+    },
+
+    mounted() {
+        let self = this;
+        let uri = self.resolve('/api/v1/message/' + self.message.ID + '/headers')
+        self.get(uri, false, function (response) {
+            self.headers = response.data
+        });
+    },
+
+}
+</script>
+
+<template>
+    <div v-if="headers" class="small">
+        <div v-for="values, k in headers" class="row mb-2 pb-2 border-bottom w-100">
+            <div class="col-md-4 col-lg-3 col-xl-2 mb-2"><b>{{ k }}</b></div>
+            <div class="col-md-8 col-lg-9 col-xl-10 text-body-secondary">
+                <div v-for="x in values" class="mb-2 text-break">{{ x }}</div>
+            </div>
+        </div>
+    </div>
+</template>