Cleanup/Reorganize app.js

[nick-w-nick]

Hello, in this PR I've gone ahead and cleaned up/reorganized the app.js file.

The changes include:

• replacing body-parser with the built-in express middleware
• fixed misc typos
• updated variable declarations to ES6
• reorganized all middleware and route imports to an "on-demand" pattern (import module only when it actually needs to be used)
• added the helmet middleware which grants automatic generic security policies
• modified server startup messaging to include crash log

I'm planning to apply this structure to the rest of the codebase in future commits but thought I'd start with the root of the application initially.

Let me know if you need any changes/etc.

Thanks!

[nick-w-nick]

@ronaldtorres I understand, it's just a specific practice I've adhered to for my app.js files without any issues.

Regardless, I think the modification within the commit I just made brings it back to a cleaner state while still retaining the usage organization.

Let me know if this change works for you.

[ronaldtorres]

@nick-w-nick yes! that change is more clean for me...