Theming (#624)

* Theming

- Custom CSS for blogs
- Custom themes for instance
- New dark theme
- UI to choose your instance theme
- Option to disable blog themes if you prefer to only have the instance theme
- UI to choose a blog theme

templates/users/edit.rs.html

@@ -1,5 +1,6 @@
 @use templates::base;
 @use template_utils::*;
+@use plume_models::instance::Instance;
 @use routes::user::UpdateUserForm;
 @use validator::ValidationErrors;
 @use routes::*;
@@ -22,6 +23,23 @@
             <label for="summary">@i18n!(ctx.1, "Summary")</label>
             <textarea id="summary" name="summary">@form.summary</textarea>
 
+            @if let Ok(themes) = Instance::list_themes() {
+                <label for="theme">@i18n!(ctx.1, "Theme")</label>
+                <select name="theme" id="theme">
+                    <option value="" @if form.theme.is_none() { selected }>@i18n!(ctx.1, "Default theme")</option>
+                    @for theme in themes {
+                        <option value="@theme" @if Some(theme.clone()) == form.theme { selected }>@theme</option>
+                    }
+                </select>
+            } else {
+                <p class="error">@i18n!(ctx.1, "Error while loading theme selector.")</p>
+            }
+
+            <label for="hide_custom_css">
+              <input type="checkbox" name="hide_custom_css" id="hide_custom_css" @if form.hide_custom_css { checked }>
+              @i18n!(ctx.1, "Never load blogs custom themes")
+            </label>
+
             <input type="submit" value="@i18n!(ctx.1, "Update account")"/>
         </form>