NCBI host fixes needed

[jameshadfield]

On the latest https://nextstrain.org/avian-flu/h5n1-d1.1/genome tree (~200 new sequences cf. yesterday!)

And in the cattle-outbreak (B3.13) tree, which uses the same NCBI sources:

[joverlee521]

Updated host map for everything except "PET FOOD" in #144

Copying comment from #144 (comment)

Note that I did not include "PET FOOD" in this change because I'm unsure how we want to label them.
Previously I added annotations for individual strains that I could track down, but it's not clear what are the latest "PET FOOD" sources.

A couple options:

1. Leave "PET FOOD" as-is and they will remain as the grey coloring
2. Map "PET FOOD" to "?" so they are excluded in the host coloring
3. Map "PET FOOD" to "Environment"

With any of these options, we can always override the general host map with specific annotations if we can track down the original source.