Migrate to Mantine UI framework

frontend/src/components/navbar/user-button.tsx

@@ -0,0 +1,28 @@
+import { UnstyledButton, Group, Avatar, Text, rem } from '@mantine/core';
+import { IconChevronRight } from '@tabler/icons-react';
+import classes from './user-button.module.css';
+
+export function UserButton() {
+  return (
+    <UnstyledButton className={classes.user}>
+      <Group>
+        <Avatar
+          src="https://images.unsplash.com/photo-1508214751196-bcfd4ca60f91?ixid=MXwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHw%3D&ixlib=rb-1.2.1&auto=format&fit=crop&w=255&q=80"
+          radius="xl"
+        />
+
+        <div style={{ flex: 1 }}>
+          <Text size="sm" fw={500}>
+            Harriette Spoonlicker
+          </Text>
+
+          <Text c="dimmed" size="xs">
+            hspoonlicker@outlook.com
+          </Text>
+        </div>
+
+        <IconChevronRight style={{ width: rem(14), height: rem(14) }} stroke={1.5} />
+      </Group>
+    </UnstyledButton>
+  );
+}