Remove Project Lifecycle Governance

The ODL project lifecycle concept has been around since the birth of ODL's governance. We've attempted to use it in various ways, but never really found it helpful. We have some Mature projects,but otherwise no one has done much with it. The few Mature projects seem to have mostly become Mature during a phase of incorrectly of thinking we would end up using the project lifecycles more. The Incubation projects seem perfectly fine being Incubation, have no motivation to become Mature. The requirement that Mature projects only depend on Mature projects has caused technical headaches for people like vorburger, k.faseela and the kernel projects. Overall, the sentiment seems to be that we should just drop this aspect of our governance.

https://www.opendaylight.org/what-we-do/lifecycle-releases