add dyes to the graphql api

[tlambert03]

This allows new graphql queries:

dyes list

{
dyes {
    name
    id
  }
}

dyes detail using name or id

{
dye(name:"Alexa Fluor 488") {
    name
    id
    spectra {
      id
      data
    }
  }
}

and filtering spectra based on category or subtype

{
spectra(category:"P" subtype:"EX"){
    id
    subtype
    category
  }
}

cc @ec363