Add contribution rules

[dstenger]

Closes #405

[jodygarnett]

This once again seems clear, and it a good example of open-source being about distribution, and not about open to drive-by participation.

This pull-request is a perfect oppertunity to as CITE SC to focus on what relationship they desire:

• This specific language should be addressed by the CITE SC

• For example to focus on communication more than the business relationship:

  Large Contribution / Multiple Files / New Files: OGC members and testbed participants are asked to coordinate larger changes with CITE SC".

[dstenger]

Thanks for your additional ideas. We will discuss those.