Cleaning codebase

[KossakowskaKarolina]

Things done:

1. Css:

• Unified units of size (px), colors (hex) and font weight.
• Changed name of file: 'login.css' suggested it applies only to 'login.html' file. I changed it to 'views.css'.
• Removed non existing classes.
• Removed properties that were overwritten by bootstrap classes.

2. Html: removed trailing slash on void elements, fixed indentations.

3. JS:

• Global variables moved to top.
• Unified names of variables. I changed all to camelCase. I changed some variables' names that were unclear.
• Var changed to let.
• Added comments to functions describing what they're doing.

General:

• Commented code and console logs removed.
• Fixed spacing and indentations.

If something needs clarification or further fixing, please let me know.