feat: custom branding (#112)

* add first concept

* remove setup status

* split config page in multiple components

* add custom branding docs

* add test email button

* fix invalid email from header

* add migration

* mount images to host

* update docs

* remove unused endpoint

* run formatter

frontend/src/pages/admin/intro.tsx

@@ -0,0 +1,59 @@
+import {
+  Anchor,
+  Button,
+  Center,
+  Container,
+  Stack,
+  Text,
+  Title,
+} from "@mantine/core";
+import Link from "next/link";
+import Logo from "../../components/Logo";
+import Meta from "../../components/Meta";
+
+const Intro = () => {
+  return (
+    <>
+      <Meta title="Intro" />
+      <Container size="xs">
+        <Stack>
+          <Center>
+            <Logo height={80} width={80} />
+          </Center>
+          <Center>
+            <Title order={2}>Welcome to Pingvin Share</Title>
+          </Center>
+          <Text>
+            If you enjoy Pingvin Share please ⭐️ it on{" "}
+            <Anchor
+              target="_blank"
+              href="https://github.com/stonith404/pingvin-share"
+            >
+              GitHub
+            </Anchor>{" "}
+            or{" "}
+            <Anchor
+              target="_blank"
+              href="https://github.com/sponsors/stonith404"
+            >
+              buy me a coffee
+            </Anchor>{" "}
+            if you want to support my work.
+          </Text>
+          <Text>Enough talked, have fun with Pingvin Share!</Text>
+          <Text mt="lg">How to you want to continue?</Text>
+          <Stack>
+            <Button href="/admin/config" component={Link}>
+              Customize configuration
+            </Button>
+            <Button href="/" component={Link} variant="light">
+              Explore Pingvin Share
+            </Button>
+          </Stack>
+        </Stack>
+      </Container>
+    </>
+  );
+};
+
+export default Intro;