Introduce an incubation phase for new functions

[drewwalters96]

Currently, functions are added directly to the workload phase which can interrupt sites that inherit documents from Treasuremap. The community determined on a recent design call to create an incubation phase that will run in its own experimental job to vet functions before they are introduced to the main workload-target phase. The criteria for when a function can move from the incubation phase to the workload phase has not yet been determined, but implementation can begin on creating the phase and job to accommodate new functions.

[jezogwza]

A possible implementation would be :

• Separate job that would run along with others
• Can be run before so that it can identify and flag functions that arent up to par.
• Should introduce some sort of validation of a function that incorporates :

•  Manifest trivial rendering issues
  

•  Deployment of the function
  

•  Eventually can incorporate the health of the function deployed
  

In the future, once we have the above, it could somehow influence the other deployment of site types, i.e. blacklisting a function that no longer passes.