[Frontend] Implement loadUser method to dynamically load home page

[amlannandy]

Description

Implemented loadUser method which runs when the app starts and fetches the profile if the user was already authenticated, otherwise redirects to login.

This is also related to #85 and continues off the token-based authentication set there.

Fixes #146

Type of change

• [x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Log in and then restart the web app

Test Configuration:

• Windows 10
• Google Chrome

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules