Add collapsible section component.

Can now collapse server categories.
Client remembers collapse state, incl. advanced appearance settings.

src/components/common/CollapsibleSection.tsx

@@ -0,0 +1,52 @@
+import Details from "../ui/Details";
+import { State, store } from "../../redux";
+import { Action } from "../../redux/reducers";
+import { Children } from "../../types/Preact";
+import { ChevronDown } from "@styled-icons/boxicons-regular";
+
+interface Props {
+    id: string;
+    defaultValue: boolean;
+
+    sticky?: boolean;
+    large?: boolean;
+
+    summary: Children;
+    children: Children;
+}
+
+export default function CollapsibleSection({ id, defaultValue, summary, children, ...detailsProps }: Props) {
+    const state: State = store.getState();
+
+    function setState(state: boolean) {
+        if (state === defaultValue) {
+            store.dispatch({
+                type: 'SECTION_TOGGLE_UNSET',
+                id
+            } as Action);
+        } else {
+            store.dispatch({
+                type: 'SECTION_TOGGLE_SET',
+                id,
+                state
+            } as Action);
+        }
+    }
+
+    return (
+        <Details
+            open={state.sectionToggle[id] ?? defaultValue}
+            onToggle={e => setState(e.currentTarget.open)}
+            {...detailsProps}>
+            <summary>
+                <ChevronDown size={20} />
+                { summary }
+                {/*<Overline type="subtle" className="overline">*/}
+                    {/*<div className="title">*/}
+                    {/*</div>*/}
+                {/*</Overline>*/}
+            </summary>
+            { children }
+        </Details>
+    )
+}