Add CONTRIBUTING.md guides

[blueprismo]

Recently opened a PR (#505) and issue (#504)
It was to me very very confusing to follow the manual scripts to contribute work.
Maybe using GHA or providing clearer documentation on how to proceed with contributors including all kinds of OS they could have might improve the development efforts in this beautiful project!

[pront]

Hi @blueprismo, intorducing a CONTRIBUTING.md is a good idea. Can you describe a bit more the challenges you faced? What scripts did you have to run?

[blueprismo]

Hello @pront and thanks for the fast response,

Headaches I got:

Semantical:

• The README.md only contains a Releasing field -> Can an external have the capability to make a release? Is it secure? (I know the answer is "you prepare a release by placing a PR").
• My personal (unasked) opinion is that instead "script to release" it changes to "how to contribute/creatingg a PR/contributing guidelines". With more detail in each of the steps.
• The script to release requires a Issue link, but there's no guidance to create an issue (or suggestion to check if the issue you are trying to report is already reported by someone else!)
• The script to release claims to need 4 dependencies, but it needs more
• Script to release could be using a Makefile (this is very opinionated, very optional).
• I am unsure if the changelog is in a desired state, how could I easily check that?

Technical:

• I had to change this file as I am working on macOS and the -i flag of sed works differently
• I don't know if the project is being funded or the infra behind it, but using Github actions as CI could automate most of these things.
• Adding GHA could also be easier to streamline the helm packaged artifact (and running linters, scanners, etc.)
• Changelog generation or "script to release" are error prone, if the script fails mid-way there's no cleanup, traps or idempotency that ensure you can safely running again without re-checking all what the script has done, which makes me loose a lot of tempo.

[pront]

@blueprismo just to be clear, the releasing process is not relevant to contributors. It is only for the project maintainers. What's the reason for touching the release scripts on your side?

[blueprismo]

That makes a lot of sense!
The lack of the contributing.md file makes me mentally fallback to the readme.md file, and therefore my missunderstanding.

Then the PR that I delivered is possibly wrong in the last commit (#505).

Anyway, to scope this issue, I think it would make sense to add [at least aminimal] CONTRIBUTING.md file with some guidelines for submitting an Issue/PR 🤗 happy to help in any way I can!

[pront]

Created this as a first step: #507

[blueprismo]

Also added a first draft in : #509 feel free to check it :)