Added local documentation

[vkresch]

Reference to a related issue in the repository

This PR fulfills the requirement from here.

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The PR adds the documentation from osi-documentation to the local osi repo to keep atomicity and integrity of git repos when changes are made to the documentation. The osi docu will be daily parsed and rebuild by the travis ci of osi-documentation.

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@pmai @jdsika pls review :)

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• My code and comments follow the style guidelines and contributors guidelines of this project.
• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests / travis ci pass locally with my changes.

[jdsika]

Where did you put the instructions on "how to create the docu images" ?