Code improvements (#1086)

* Extract code into hook
* Refactor code to remove let
* Reformat code
* Extract version-info-modal into components
* Use main block in landinglayout
* Add fixedWidth and classname attribute to IconButton

Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>

src/components/landing-layout/footer/version-info/version-info-modal.tsx

@@ -0,0 +1,38 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import React from 'react'
+import { CommonModal, CommonModalProps } from '../../../common/modals/common-modal'
+import { Modal, Row } from 'react-bootstrap'
+import { VersionInfoModalColumn } from './version-info-modal-column'
+import frontendVersion from '../../../../version.json'
+import { useSelector } from 'react-redux'
+import { ApplicationState } from '../../../../redux'
+import equal from 'fast-deep-equal'
+
+export const VersionInfoModal: React.FC<CommonModalProps> = ({ onHide, show }) => {
+  const serverVersion = useSelector((state: ApplicationState) => state.config.version, equal)
+
+  return (
+    <CommonModal data-cy={ 'version-modal' } show={ show } onHide={ onHide } closeButton={ true }
+                 titleI18nKey={ 'landing.versionInfo.title' }>
+      <Modal.Body>
+        <Row>
+          <VersionInfoModalColumn
+            titleI18nKey={ 'landing.versionInfo.serverVersion' }
+            version={ serverVersion.version }
+            issueTrackerLink={ serverVersion.issueTrackerUrl }
+            sourceCodeLink={ serverVersion.sourceCodeUrl }/>
+          <VersionInfoModalColumn
+            titleI18nKey={ 'landing.versionInfo.clientVersion' }
+            version={ frontendVersion.version }
+            issueTrackerLink={ frontendVersion.issueTrackerUrl }
+            sourceCodeLink={ frontendVersion.sourceCodeUrl }/>
+        </Row>
+      </Modal.Body>
+    </CommonModal>
+  )
+}