Use `ingest/scripts` to match `phylogenetic/scripts`

[j23414]

Description of proposed changes

While chatting about a standard directory structure of the pathogen repository, we noticed that zika was using both phylogenetic/scripts and ingest/bin.

This PR picks bin to keep things consistent.

Additionally, deleted an unused script.

Related issue(s)

Checklist

• [x] Checks pass

[victorlin]

This PR picks bin to keep things consistent.

I'm all for consistency! Noting that there is a split across @nextstrain:

• ingest/bin/*: 12 files
• ingest/scripts/*: 6 files
• phylogenetic/scripts/*: 13 files
• phylogenetic/bin/*: 7 files

If zika was just a one-off then I would suggest being consistent with other repos. But there's a clear lack of consistency across many repos. Let's open an issue in nextstrain/private where we can discuss and decide which to use, then update this PR + other repos with the decision?

[j23414]

Updated this PR with the decision to use "scripts" instead of "bin". Ready for review