Create basic zuul infrastucture in k8s

Here has been created a basic zuul setup. The elements included here are:

• A namespace where the zuul cluster works in.
• Configmaps including elements for zuul and zuul elements configuration.
• A zuul scheduler and a service to access it.
• A data base (mariadb).
• Zookeeper, which will be needed later to communicate with nodepool.
• A zuul executor, which will execute the jobs in the workers provide by nodepool.

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