Report error when adding product with `nodata:` value outside the range of the data type

[pjonsson]

When upgrading to 1.9, I found we had a product definition that looks like this:

name: a_name
description: Something
metadata_type: eo3
license: CC-BY-4.0
metadata:
  product:
    name: a_name
measurements:
  - name: "cld"
    dtype: uint8
    nodata: NaN
    units: "percent"

and it seems to be accepted by datacube product add file.yaml with both 1.8 and 1.9. I don't know the history for why our product definition looks the way it does, but it would be nice if datacube had given an error when trying to add this.

Edit: tests/data/ga_s1_nrb_iw_hh_0.odc-product.yaml contains:

  - name: gamma0_to_sigma0_ratio
    dtype: float32
    nodata: .nan
    units: '1'

which uses a floating point type so NaN is present, but the leading period doesn't look like it's matching the schema definition:

            nodata:
              oneOf:
                - type: number
                - enum: [nan, NAN, NaN, Inf, -Inf]