Change default zstd-compress-level to 19

[dholth]

Checklist

• [X] I added a descriptive title
• [X] I searched open requests and couldn't find a duplicate

What is the idea?

167 shows that our current default compression level of -22 (from the command line, guarded behind zstd --ultra) uses 600+ MB. -19, the highest non-ultra level, uses a little less than 100MB and will be faster to compress. Maybe the default level should be 19, or even a lower amount.

Why is this needed?

No response

What should happen?

No response

Additional Context

No response

[jezdez]

I think it can't hurt to lower the default to 19 now and investigate further if a further decrease makes sense.

[dholth]

However it's conda-build setting 22 unfortunately.

[jezdez]

True, gotta get https://github.com/conda/conda-build/pull/4661 out

[dholth]

Pretty sure we have one default level in the api and a second one in the cli parsing that should be updated

[dholth]

169