Refactor File lock documentation

- Move to new location according to
  https://gitlab.com/gitlab-org/gitlab-ce/issues/3349
- Use new images

doc/user/projects/file_lock.md

+# File Lock
+
+>**Note:**
+This feature was [introduced][ee-440] in GitLab EE 8.9.
+
+---
+
+>**Note:**
+This feature needs to have a license with the "File Lock" option enabled. If
+you are using Enterprise Edition but you don't see the "Lock" button,
+ask your GitLab administrator. Check GitLab's [pricing page] for more information.
+
+GitLab gives you the ability to lock any file or folder in the repository tree
+reserving you the right to make changes to that file or folder. **Locking only
+works for the default branch you have set in the project's settings** (usually
+`master`).
+
+The file locking feature is useful in situations when:
+
+- Multiple people are working on the same file and you won't to avoid merge
+  conflicts.
+- Your repository contains binary files in which situation there is no easy
+  way to tell the diff between yours and your colleagues' changes.
+
+---
+
+If you lock a file or folder, then you are the only one who can push changes to
+the repository where the locked objects are located. Locked folders are locked
+recursively.
+
+Locks can be created by any person who has [push access] to the repository; i.e.,
+developer and higher level. Any user with master permissions can remove any
+lock, no matter who is its author.
+
+## Locking
+
+To lock a file, navigate to the repository tree under the **Code > Files** tab,
+pick the file you want to lock and hit the "Lock" button.
+
+![Locking file](img/file_lock.png)
+
+---
+
+To lock an entire folder look for the "Lock" link next to "History".
+
+![Locking folder](img/file_lock_folders.png)
+
+---
+
+After you lock a file or folder, it will appear as locked in the repository
+view.
+
+![Repository view](img/file_lock_repository_view.png)
+
+---
+
+To unlock it follow the same procedure or see the following section.
+
+## Viewing/Managing existing locks
+
+To view or manage every existing lock, navigate to the
+**Project > Code > Locked Files** section. Only the user that created the lock
+and Masters are able to remove the locked objects.
+
+![Locked Files](img/file_lock_list.png)
+
+[ee-440]: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/440 "File Lock"
+[pricing page]: https://about.gitlab.com/pricing
+[push access]: ../../permissions/permissions.md

doc/workflow/README.md

@@ -8,7 +8,7 @@
 - [Importing to GitLab](doc/importing/README.md)
 - [Keyboard shortcuts](shortcuts.md)
 - [File finder](file_finder.md)
-- [File lock](file_lock.md)
+- [File lock](../user/projects/file_lock.md)
 - [Labels](labels.md)
 - [Issue weight](issue_weight.md)
 - [Manage large binaries with git annex](git_annex.md)

doc/workflow/file_lock.md

-# File Lock
-
->**Note:**
-This feature was [introduced][ee-440] in GitLab 8.9.
-
----
-
-GitLab enables us to lock any file or path in repository tree. If you have a lock
-then you are the only one who can push changes to the repository where locked objects are changed.
-Locks can be created by any person who has access to push the code; i.e., developer and higher level.
-The user with master permissions level can remove any lock, no matter who is the author of the lock.
-
-## Locking
-
-To lock any file or folder open it in GitLab Code viewer and you will see appropriate link or button
-
-![Locking file](file_lock/file_lock.png)
-
-![Locking folder](file_lock/folder_lock.png)
-
-
----
-
-## Viewing/Managing existing locks
-
-To view or manage every existing lock go to the **Project > Code > Locked Files** section.
-
-![ocked Files](file_lock/locked_files.png)
-
----
-## License note
-
-To activate this feature you have to have a license with the "File Lock" option enabled.
-
----
-
-[ee-440]: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/440 "File Lock"