Show sub-folders indented

Problem/Motivation

When displaying a long list of folders that includes many sub-folders with similar names, it's hard to follow through them and easy to get confused as to which one is desired.

Steps to reproduce

In code, get a list of folders that have multiple and multiple layers of sub-folders and add them to a select list.

Proposed resolution

Add an indentation to the sub-folders in the list.

Remaining tasks

• Code review
• Merge patch

User interface changes

Adds an indentation on sub-folders, when all folders are listed.

API changes

None.

Data model changes

None.