Add Contribution guide

[camilamacedo86]

We need to add a new contributing guide with the basic info for new contributors, such as the i.e: https://github.com/kubernetes-sigs/kubebuilder/blob/master/CONTRIBUTING.md

[lodenrogue]

How complex should this file be? Which parts of the kubernetes document apply to this project?

[camilamacedo86]

The goal of the Contributing guidelines is to add the required info for people to know how to contribute to the project. The Kubebuilder guidelines are an example to let you know how to do that.

I would expect in the audit one something like:

• Contributing steps
• How to build audit locally
• What to do before submitting a pull request ( for us here is run make lint )
• PR Process ( after we do the task Add GitHub Action to check the PR title #133 it will be == )
• Where the CI Tests are configured
• Where the audit reports are available (https://operator-framework.github.io/audit/)
• How the audit reports are built