fix: Move content into to frontend directory

Doing this BEFORE the merge prevents a lot of merge conflicts.

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

frontend/src/components/login-page/auth/via-ldap.tsx

@@ -0,0 +1,72 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { FormEvent } from 'react'
+import React, { useCallback, useState } from 'react'
+import { Button, Card, Form } from 'react-bootstrap'
+
+import { Trans, useTranslation } from 'react-i18next'
+import { doLdapLogin } from '../../../api/auth/ldap'
+import { fetchAndSetUser } from './utils'
+import { AuthError as AuthErrorType } from '../../../api/auth/types'
+import { UsernameField } from './fields/username-field'
+import { PasswordField } from './fields/password-field'
+import { AuthError } from './auth-error/auth-error'
+import { useOnInputChange } from '../../../hooks/common/use-on-input-change'
+
+export interface ViaLdapProps {
+  providerName: string
+  identifier: string
+}
+
+/**
+ * Renders the LDAP login box with username and password field.
+ */
+export const ViaLdap: React.FC<ViaLdapProps> = ({ providerName, identifier }) => {
+  useTranslation()
+
+  const [username, setUsername] = useState('')
+  const [password, setPassword] = useState('')
+  const [error, setError] = useState<AuthErrorType>()
+
+  const onLoginSubmit = useCallback(
+    (event: FormEvent) => {
+      doLdapLogin(identifier, username, password)
+        .then(() => fetchAndSetUser())
+        .catch((error: Error) => {
+          setError(
+            Object.values(AuthErrorType).includes(error.message as AuthErrorType)
+              ? (error.message as AuthErrorType)
+              : AuthErrorType.OTHER
+          )
+        })
+      event.preventDefault()
+    },
+    [username, password, identifier]
+  )
+
+  const onUsernameChange = useOnInputChange(setUsername)
+  const onPasswordChange = useOnInputChange(setPassword)
+
+  return (
+    <Card className='bg-dark mb-4'>
+      <Card.Body>
+        <Card.Title>
+          <Trans i18nKey='login.signInVia' values={{ service: providerName }} />
+        </Card.Title>
+        <Form onSubmit={onLoginSubmit}>
+          <UsernameField onChange={onUsernameChange} invalid={!!error} />
+          <PasswordField onChange={onPasswordChange} invalid={!!error} />
+          <AuthError error={error} />
+
+          <Button type='submit' variant='primary'>
+            <Trans i18nKey='login.signIn' />
+          </Button>
+        </Form>
+      </Card.Body>
+    </Card>
+  )
+}