Spread contribution guide to all repositories

[innerjoin]

We have an awesome contribution guide written by @SBI-. Add a CONTRIBUTING.md file to each repository and point to the Contributing.md file in this repository. If there are any additional rules to follow, enhance the CONTRIBUTING.md file of a specific repository to hold that information

[innerjoin]

Place a CONTRIBUTING.md in each project that contains source code.
My suggestion would be the following content:

Required section

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Contributing to

Please read our general contribution guide. It's content applies to all repositories of the jazz-community organization.

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Optional Section

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<place any additional guidance, like quality requirements (test coverage, ...) that are specific to the repository here>

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[innerjoin]

@SBI- Seems to be done for all repos, do you agree?

[SBI-]

Git connector is still missing one. I will add one with the next release.

[innerjoin]

You are right....