Add collapsible section component.

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

src/components/ui/Details.tsx

@@ -1,16 +1,29 @@
-import styled from "styled-components";
+import styled, { css } from "styled-components";
 
-export default styled.details`
+export default styled.details<{ sticky?: boolean, large?: boolean }>`
     summary {
+        ${ props => props.sticky && css`
+            top: -1px;
+            z-index: 10;
+            position: sticky;
+        ` }
+
+        ${ props => props.large && css`
+            padding: 5px 0;
+        ` }
+
         outline: none;
+        display: flex;
+        cursor: pointer;
         list-style: none;
+        align-items: center;
         transition: .2s opacity;
 
         &::marker, &::-webkit-details-marker {
             display: none;
         }
 
-        svg {
+        > svg {
             flex-shrink: 0;
             transition: .2s ease transform;
         }