Update CONTRIBUTING.md

[XV02]

Summary of changes

This pull request includes following changes.

• Adds naming conventions docs.

Description

Added Naming conventions for branches and commits to the Contributing markdown file.

Closes #526
Related #460
Related #515

Type of change

• Documentation

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have confirmed my fix is effective or that my feature works

[piste-jp]

I strongly disagree with this PR.

DO NOT change current development process without any discussion with members of this project!!!!

First of all, you MUST open issue and make hearing about your idea.

[XV02]

Turning into draft until we reach an agreement with the community contributors.