Slightly improve the media experience (#452)

* Slightly improve the media experience

- Use a grid to display the list of media
- Add icons for non-image media preview
- Paginate the gallery
- Add links to the gallery in the editor and in the profile settings to make it more discoverable when you need it

Fixes #432

* Allow video and audio tags in SafeString

Otherwise we can't display their preview, nor show them in articles

Also show controls by default for these two elements

* Show fallback images for audio and unknown files, to make them more visible

* Add a new constructor to SafeString when the input is trusted and doesn't need to be escaped.

And use it to generate media previews.

* Make it possible to insert video/audio in articles

po/plume/ja.po

@@ -240,6 +240,13 @@ msgstr "自分のアカウントを編集"
 msgid "Your Profile"
 msgstr "自分のプロフィール"
 
+msgid "To change your avatar, upload it in your gallery and select from there."
+msgstr ""
+
+#, fuzzy
+msgid "Upload an avatar"
+msgstr "アバターとして使う"
+
 #, fuzzy
 msgid "Display name"
 msgstr "表示名"
@@ -531,6 +538,15 @@ msgstr "サブタイトル"
 msgid "Content"
 msgstr "コメント"
 
+msgid ""
+"You can upload medias to your gallery, and copy their Markdown code in your "
+"articles to insert them."
+msgstr ""
+
+#, fuzzy
+msgid "Upload media"
+msgstr "アップロード"
+
 # src/template_utils.rs:144
 msgid "Tags, separated by commas"
 msgstr ""
@@ -709,9 +725,17 @@ msgstr "アップロード"
 msgid "You don't have any media yet."
 msgstr "メディアがまだありません。"
 
+#, fuzzy
+msgid "Content warning: {0}"
+msgstr "コンテンツの警告"
+
 msgid "Delete"
 msgstr "削除"
 
+#, fuzzy
+msgid "Details"
+msgstr "メディアの詳細"
+
 msgid "Media upload"
 msgstr "メディアのアップロード"