pimp README & co to be SAP open source compliant

AUT-1836

CONTRIBUTING.md

@@ -0,0 +1,19 @@
+# Contributing
+
+Contributions are welcome.
+
+If you have a suggestion that would make this better, please fork the repo and 
+create a pull request. You can also simply open an issue.
+
+1. Fork the Project
+2. Create your Feature Branch (`git checkout -b feature/***`)
+3. Commit your Changes (`git commit -m 'Added feature: ...'`)
+4. Push to the Branch (`git push origin feature/***`)
+5. Open a Pull Request
+
+## Developer Certificate of Origin (DCO)
+
+Due to legal reasons, contributors will be asked to accept a DCO when they 
+create the first pull request to this project. This happens in an automated 
+fashion during the submission process. SAP uses 
+[the standard DCO text of the Linux Foundation](https://developercertificate.org/).

README.md

@@ -1,12 +1,39 @@
 # php-suite-api
 
-Helper classes to use Emarsys Suite API
+PHP wrapper library for the Emarsys Suite v2 API. 
 
-## How to create new release
+This library is for accessing the v2 API using Escher authentication (aka 
+internal API). WSSE authentication (aka "public" v2 API) is not supported.
 
-When you want to release a new version from the package, please add a tag with the current version on GitHub.
+## Requirements
+
+The package supports PHP 8+
+
+You will need an Escher key provided by Emarsys to use this library.
+
+## How to do useful things
+
+### Create a new release
+
+When you want to release a new version from the package, please add a tag with 
+the current version on GitHub.
 
 ```
 git tag 2.0.4
 git push --tags
 ```
+
+# Contributing
+
+See [Contribution guideline](https://github.com/emartech/php-suite-api/blob/master/CONTRIBUTING.md).
+
+# Code of Conduct
+
+See [Code of Conduct here](https://github.com/emartech/.github/blob/main/CODE_OF_CONDUCT.md).
+
+# Licensing
+
+Copyright 2016-2023 SAP SE or an SAP affiliate company and php-suite-api 
+contributors. Please see our 
+[LICENSE](https://github.com/emartech/php-suite-api/blob/master/LICENSE) for 
+copyright and license information.