Organize Holocron Dashboard Folder structure

The folder structure in Holocron Dashboard is a bit too confusing. In order to ease new font-end developer onboarding, I suggest the following folder structure which should not raise any questions.

src/
  api/
  utils/
  ui/
  __mocks__/

api contains all the files that are related to holocron-api.

utils contains all the folders that store utility code that are not directly rendered onto the screen

ui contains all the folders that are rendered directly onto the screen.

In addition:

• there will be no folders within api folder (just typescript files).
• all the folders within utils, ui must import to index, and cannot have more than depth 1. For example: this is valid:

ui/
 MyComponent/
  Foo.test.tsx
  Foo.tsx
  index.tsx

However, the following is not valid because it exceeds depth 1:

ui/
 MyComponent/
   Foo/
     Foo.test.tsx
     Foo.tsx
   index.tsx