[WebIDE] Web IDE does not handle symlinks

MR: Pending

Description

The Web IDE does not handle symlinks very well:

1. It treats them as a regular file with the linked path as the content of the file.
2. After trying to edit the file, it shows this as a new file in source control. After trying to commit, the commit fails saying that the file already exists.

web_ide_symlink_bug

Acceptance criteria

• Opening a symlink actually opens the file it's linked to. If this is too difficult, then at least replicate the behavior of the single file editor.
• Symlinks can be moved/removed.

Investigation

VSCode has some baked-in handling for FileType.SymbolicLink.