WX-1252 Per-backend runtime attributes

[aednichols]

Getting the tests plumed through right was the trickiest part. Here are the test correspondences with GHA suites:

• biscayne_new_runtime_attributes_lifesciences: Centaur Papi V2 Beta, Centaur GCP Batch
• biscayne_new_runtime_attributes_tes: Centaur TES
• biscayne_new_runtime_attributes_local: Centaur Local

There appears to be some spec confusion wherein the per-cloud scopes are referred to as "object" but have the syntax of a namespace (and not a map, because map keys are quoted):

runtime {
  gcp: {
    ...
  }
}

Immediately above we're using object { though.

runtime {
  inputs: object {
    foo: object { 
      localizationOptional: true
    }
  }
}

I decided in favor of object on the basis of 2/3 majority between the examples and being called that in the prose.

[jgainerdewar]

LGTM! Thanks for the walkthrough earlier.

[THWiseman]

Nice work!