Important to get file data for any file that has no content set yet: we
need this information in order to build a previe for changed/staged
files if they were not yet opened in the editor

If an entry has been removed from the tree and later, during the same
session, a user is trying to add a new item with the same name/path we
should allow for that as long as the original entry is marked with
`deleted`.

Fix IDE editor to update dimensions on show change

Closes #45120

See merge request gitlab-org/gitlab-ce!30135

Update window's URL after entry's re-name

Set proper hook for correct fileLanguage

Filtered out `moved` entries from the tree

When removing the last file from a folder in WebIDE, do not remove the
folder from the view. We keep those to give users possibility to
re-upload files to the same folders.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/60860

**Why?**
The branch HEAD could be changed since the
IDE was opened. This leads to user's unintentionally
creating commits that overwrite other changes.

https://gitlab.com/gitlab-org/gitlab-ce/issues/59023

- On CMD+S when editor is focused
- On editor blur
- When file is created in tree
- When file is removed in tree
- When file is renamed in tree

- Pull the new MR option out into it's own component
- Default MR checkbox to true when creating a new MR and committing to a
  branch that does not have an MR
- Still change the MR checkbox to false when a user is on a branch that
  already has an MR
- Hide MR option when on a branch that already has an MR and committing
  to current branch
- Don't default to true when committing directly to master

Resolves https://gitlab.com/gitlab-org/gitlab-ce/issues/60107