restructure presentation layer

- Move most GUI related code to /presentation
- Move components to /components (separate from bootstrap and style)
- Move shared components helpers to /components/shared
- Rename Bootstrapping to bootstrapping to enforce same naming
  convention in /presentation

src/presentation/components/TheFooter/DownloadUrlList.vue

@@ -0,0 +1,72 @@
+<template>
+  <span 
+    class="container"
+    v-bind:class="{ 'container_unsupported': !hasCurrentOsDesktopVersion, 'container_supported': hasCurrentOsDesktopVersion }">
+    <span class="description">
+      <font-awesome-icon class="description__icon" :icon="['fas', 'desktop']"  />
+      <span class="description__text">For desktop:</span>
+    </span>
+    <span class="urls">
+      <span class="urls__url" v-for="os of supportedDesktops" v-bind:key="os">
+        <DownloadUrlListItem :operatingSystem="os" />
+      </span>
+    </span>
+  </span>
+</template>
+
+<script lang="ts">
+import { Component, Vue } from 'vue-property-decorator';
+import { Environment } from '@/application/Environment/Environment';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import DownloadUrlListItem from './DownloadUrlListItem.vue';
+
+@Component({
+  components: { DownloadUrlListItem },
+})
+export default class DownloadUrlList extends Vue {
+  public readonly supportedDesktops: ReadonlyArray<OperatingSystem>;
+  public readonly hasCurrentOsDesktopVersion: boolean = false;
+
+  constructor() {
+    super();
+    const supportedOperativeSystems = [OperatingSystem.Windows, OperatingSystem.Linux, OperatingSystem.macOS];
+    const currentOs = Environment.CurrentEnvironment.os;
+    this.supportedDesktops = supportedOperativeSystems.sort((os) => os === currentOs ? 0 : 1);
+    this.hasCurrentOsDesktopVersion = supportedOperativeSystems.includes(currentOs);
+  }
+}
+</script>
+
+<style scoped lang="scss">
+@import "@/presentation/styles/media.scss";
+
+.container {
+  display:flex;
+  flex-wrap: wrap;
+  justify-content: space-around;
+  &_unsupported {
+    opacity: 0.9;
+  }
+  &_supported {
+    font-size: 1em;
+  }
+  .description {
+    &__icon {
+      margin-right: 0.5em;
+    }
+    &__text {
+      margin-right: 0.3em;
+    }
+  }
+}
+.urls {
+  &__url {
+    &:not(:first-child)::before {
+      opacity: 0.5;
+      content: "|";
+      font-size: 0.6rem;
+      padding: 0 5px;
+    }
+  }
+}
+</style>