Rewrite of WebUI (#245)

Rewrite of the UI using Typescript, Vue3, Windicss and Vite. The design should  be close to the current one with some changes:
- latest pipeline in a sidebar on the right
- secrets and registry as part of the repo-settings (secrets and registry entries shouldn't be used as much so they can be "hidden" under settings IMO)
- start page shows list of active repositories with button to enable / add new ones (currently you see all repositories and in most cases you only add new repositories once in a while)

web/src/components/build-feed/BuildFeedSidebar.vue

@@ -0,0 +1,48 @@
+<template>
+  <div
+    v-if="isBuildFeedOpen"
+    class="flex flex-col overflow-y-auto items-center bg-white dark:bg-dark-gray-800 dark:border-dark-500"
+  >
+    <router-link
+      v-for="build in sortedBuildFeed"
+      :key="build.id"
+      :to="{ name: 'repo-build', params: { repoOwner: build.owner, repoName: build.name, buildId: build.number } }"
+      class="
+        flex
+        border-b
+        py-4
+        px-2
+        w-full
+        hover:bg-light-300
+        dark:hover:bg-dark-gray-900 dark:border-dark-gray-600
+        hover:shadow-sm
+      "
+    >
+      <BuildFeedItem :build="build" />
+    </router-link>
+
+    <span v-if="sortedBuildFeed.length === 0" class="text-gray-500 m-4">No pipelines have been started yet.</span>
+  </div>
+</template>
+
+<script lang="ts">
+import { defineComponent } from 'vue';
+
+import BuildFeedItem from '~/components/build-feed/BuildFeedItem.vue';
+import useBuildFeed from '~/compositions/useBuildFeed';
+
+export default defineComponent({
+  name: 'BuildFeedSidebar',
+
+  components: { BuildFeedItem },
+
+  setup() {
+    const buildFeed = useBuildFeed();
+
+    return {
+      isBuildFeedOpen: buildFeed.isOpen,
+      sortedBuildFeed: buildFeed.sortedBuilds,
+    };
+  },
+});
+</script>