viewer: migrate to vue 3, general refactoring and cleanup

Non-exhaustive list of fixes and improvements done at the same time:

- html default background to grey (avoids white flash during init)
- unified links behavior
- added more theme variables
- removed the flex-expand transition (it wasn't working) and replaced it
  with a slide
- fixed LdLoading not centered on the content
- title on removable tags
- fixed an issue with encoded URI from vue-router
- unified Item resource URLs
- removed the iframe for PlainTextViewer (it wasn't working properly)
  and replaced it with a pre
- fixed clear and search buttons tabindex
- fixed the information panel bumping up during the fade animation of
  tag's dropdown
- fixed some focus outlines not appearing correctly
- moved CSS variables to the :root context
- Code cleaning

GitHub: closes #217
GitHub: closes #300
GitHub: closes #297
GitHub: closes #105
GitHub: closes #267
GitHub: closes #275
GitHub: closes #228
GitHub: closes #215
GitHub: closes #112

2 files changed, 34 insertions, 14 deletions

diff --git a/viewer/src/components/async/Markdown.vue b/viewer/src/components/async/AsyncLdMarkdown.vue
index c4e282b..213c11c 100644
--- a/viewer/src/components/async/Markdown.vue
+++ b/viewer/src/components/async/AsyncLdMarkdown.vue
@@ -18,26 +18,28 @@
 -- along with this program.  If not, see <https://www.gnu.org/licenses/>.
 -->
 
+<!-- eslint-disable vue/no-v-html -->
 <template>
-  <div :class="$style.markdown" v-html="html" />
+  <div
+    :class="$style.markdown"
+    v-html="html"
+  />
 </template>
 
-<script lang="ts">
-import marked from "marked";
-import { Component, Prop, Vue } from "vue-property-decorator";
+<script setup lang="ts">
+import { marked } from 'marked';
+import { computed } from 'vue';
 
-@Component
-export default class Markdown extends Vue {
-  @Prop({ required: true }) readonly markdown!: string;
+const props = defineProps({
+  markdown: { type: String, required: true },
+});
 
-  get html(): string {
-    return marked(this.markdown);
-  }
-}
+const html = computed(() => marked(props.markdown));
 </script>
 
 <style lang="scss" module>
 .markdown {
+  color: white;
   line-height: 1.7;
   word-wrap: break-word;
 
diff --git a/viewer/src/components/async/index.ts b/viewer/src/components/async/index.ts
index 5a7d9a6..05a0814 100644
--- a/viewer/src/components/async/index.ts
+++ b/viewer/src/components/async/index.ts
@@ -1,4 +1,22 @@
-// Declare async constants for internal components
-// Their name can't start with 'Ld'
+/* ldgallery - A static generator which turns a collection of tagged
+--             pictures into a searchable web gallery.
+--
+-- Copyright (C) 2019-2022  Guillaume FOUET
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
 
-export const Markdown = () => import(/* webpackChunkName: "markdown" */ "./Markdown.vue");
+import { defineAsyncComponent } from 'vue';
+
+export const LdMarkdown = defineAsyncComponent(() => import(/* webpackChunkName: "markdown" */ './AsyncLdMarkdown.vue'));