Add coding conventions to repo

[simon-bourque]

TASK

Description:

We need to come up with coding conventions to make sure everyone is on the right page when it comes to naming, style, etc.

Motivation:

Coming up with coding conventions will make the code more readable and consistent.

Completion Criteria:

• CONTRIBTUTING file added to the repo
• Coding conventions section added to CONTRIBUTING file
• Update existing code with new conventions