docs: Add contribution guide

[mbfakourii]

Pull Request

• Report security issues confidentially.
• Any contribution is under this license.
• Link this pull request to an issue.

Issue

Closes: #917

Approach

Add CONTRIBUTING.md

Tasks

• [ ] Add tests
• [ ] Add changes to documentation (guides, repository pages, code comments)

[parse-github-assistant[bot]]

Thanks for opening this pull request!

[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (a836d8e) 38.55% compared to head (4e7ba14) 38.55%.

:exclamation: Current head 4e7ba14 differs from pull request most recent head 835a1db. Consider uploading reports for the commit 835a1db to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #916 +/- ## ======================================= Coverage 38.55% 38.55% ======================================= Files 59 59 Lines 3328 3328 ======================================= Hits 1283 1283 Misses 2045 2045 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.