Add revisions dialog (#485)

* Add mock files

Note that revisions-list needs to be called revisions in the reality to be confirm with the API spec, but our mocking solution doesn't allow that...

* Add revisions API calls

* Fix line endings in mock files

* Extend CommonModal to accept size and additionalClasses

* Clarify variable name in API request

* Add react-diff-viewer as dependency

* Add revision chooser modal

* Fix type of route params

* Added and updated mock files

* Added user-icon list per revision

* Added translation to alt text of avatars

* Updated mock file to remove inconsistencies

* Add caching for revisions

* Sort mock file revisions-list descending by timestamp

* Pre-select first/newest revision on first modal open

* Regenerated yarn.lock file from scratch

* Applied requested changes in variable names and line lengths

* User UserAvatar component instead of manually set image

* Move revision-modal-list-entry to own component

* Removed unnecessary return statements

src/components/editor/document-bar/revisions/revision-button.tsx

@@ -0,0 +1,18 @@
+import React, { Fragment, useState } from 'react'
+import { TranslatedIconButton } from '../../../common/icon-button/translated-icon-button'
+import { RevisionModal } from './revision-modal'
+
+export interface RevisionButtonProps {
+  noteContent: string
+}
+
+export const RevisionButton: React.FC<RevisionButtonProps> = ({ noteContent }) => {
+  const [show, setShow] = useState(false)
+
+  return (
+    <Fragment>
+      <TranslatedIconButton size={'sm'} className={'mx-1'} icon={'history'} variant={'light'} i18nKey={'editor.documentBar.revision'} onClick={() => setShow(true)}/>
+      <RevisionModal show={show} onHide={() => setShow(false)} titleI18nKey={'editor.modal.revision.title'} icon={'history'} noteContent={noteContent}/>
+    </Fragment>
+  )
+}