Ground control - develop sidebar

[koyuul]

Objective:
Begin ground control development by implementing a sidebar. This sidebar will eventually have much more functionality, however let's start small.

Purpose:
Sidebar should have similar functionality as VSCode's sidebar:

• Ability to grab and drag items
• Ability to have folders of items, which are collapsible
• Bonus/if extra time: Dropping an element in the main area should have an effect on the main area (eg: change background). Essentially would mimic dragging a file into the work area in VSCode, and having it show the contents of the file.

For this task, please include the following items in the sidebar:

file_a
file_b
file_c
folder_a:
   a_file_a
   a_file_b

Current code written:
You are working with a fresh nano-react-app template.