Add a requirement for deprecating duplicated code

This patch updates graduation requirements related to scope.  The requirements
currently say a project must not duplicate the scope of another project.
However, we have some cases where a project intentionally duplicates
functionality with the intent of replacing it (Neutron, Cinder).

In that case, I believe we should have an additional requirement that the new
project may not graduate until it has reached a level of functionality and
maturity where we're able to deprecate the component it is replacing with a
known timeline for removal.

Change-Id: I5305e2f80ebc3c78ef74b0957337fe11c3f3de08
Add missed mission statement for Data Processing

The specified mission statement is rewording done using comments of TC
members and based on the mission statement that was proposed while
incubating. The new wording was accepted by Savanna folks.

Here is an incubation application:
https://wiki.openstack.org/wiki/Savanna/Incubation

Change-Id: I814084de631d8aa245101476b7c46ca3eaede200
Merge "Add a requirement for deprecating duplicated code"
Merge "Add missed mission statement for Data Processing"