read ProjectStage also from a few other places

We currently only read the ProjectStage setting from "org.apache.deltaspike.ProjectStage".

We should also try to read the info from the other ususal suspects:

• javax.faces.PROJECT_STAGE
• faces.PROJECT_STAGE

We have 2 options to do so:
1.) introduce a SPI and make it expandable. But I honestly doubt this is worth the hassle.
2.) Just add the other locations and iterate through them directly in the ProjectStageProducer.

I honestly prefer 2. Not as perfectly as clean, but way easier and usually this i snothing a user will change anyway.