Flag potential lineages for new Nextstrain clades

[joverlee521]

Context

Requested by @trvrb in today's forecasting-automation meeting:

Separately, I’m still running Mathematica version of fitting linear regression to logit-transformed frequencies to demarcate our >0.05 per day growth in frequency threshold

• Could we write a small script to scan forecast-ncov results for this threshold? It really should be clade-in-question vs “other” however.
• Should be able to convert relative growth advantage to per-day growth rate (site: delta in models)
• Multiply Pango lineage frequency by relative fitness will give mean fitness
• Per day relative fitness is in the model already

[corneliusroemer]

How would this work for regions for which we have no countries included, e.g. South America/Africa? Using this flaggin strategy would increase clade bias towards high income/sequencing countries. See #64