This fixes a bug where the file templates would not be cleared
after changing the template type.
Previously the templates would get pushed into the array
creating a list of templates for the different types.
This changes that by clearing the templates array
when the template type gets changed.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52487

This file tree displays all the diff files in a tree like format
Each file is taken and converted into a tree with folders
Each folder can be toggled open & closed
Clicking a file will scroll to the diff file & highlight with a glow affect

Searching the tree list will search only files & return a list of the
files without any folders

Each file row contains an icon to show changed, new file or deleted
Each row will also contain the added & removed lines count

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14249

Keep IDE RightPane views alive

See merge request gitlab-org/gitlab-ce!21980

**Why?**
- This is needed for the Web Terminal feature.
  https://gitlab.com/gitlab-org/gitlab-ee/issues/5426

**Notes:**
- Introduces a `pane` Vuex module.
- Some views should not be kept alive (i.e. job details).
  This is why a `keepAlive` flag was introduced for views.

Closes #51912