Add optional aliases field to JSON for a codec

[DennisHeimbigner]

I would like to propose a new, optional field to be added to the JSON codec format.
The field is called "aliases" and its value is a dictionary where the key provides information about the genesis of the alias and the value of the key is the alias itself.
The immediate goal is to allow the specification of HD5 filter ids in associate with a NumCodecs identifier. So for example, one might have this:

{
        "id": "bz2",
        "level": 1,
        "aliases": {"hdf5": "307", "NumCodecs": ["bzip2", "bzip"]}
}

This indicate that the NumCodecs "bz2" filter is the same as the HDF5 filter with assigned id 307. It also indicates that the NumCodec IDS "bzip2" and "bzip" should be considered aliases for "bz2"

Semantically, since it is optional, any implementation is free to ignore the "aliases" field and is also free to ignore any entries in its associated aliases dictionary.

[DennisHeimbigner]

Withdrawn for further consideration.

[DennisHeimbigner]

Re-opened with an extended example.