ADT aware response

[jkanche]

• preflight should include ADT aware response
• adt_normalization (would send size factors at some point)

[LTLA]

New preflight response structure looks like:

    {
      annotations: { default: [ 'AAACCTGAGACCACGA-1' ] },
      features: {
        RNA: { fields: [Object], common: 33538 },
        ADT: { fields: [Object], common: 17 }
      }
    }

fields define the chosen fields for each modality, common defines the number of common features.