Additional adjustments in the generator modules

[nevrome]

• removed the already hidden space-time-interpolation code; maybe I'll reactivate this for a specific analysis, but beyond that it's too obscure
• turned on vcf writing for admixpops

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 6.62%. Comparing base (8f28c89) to head (a463189).
⚠️ Report is 3 commits behind head on prepare_for_monorepo_inclusion.

Additional details and impacted files

@@                      Coverage Diff                       @@
##           prepare_for_monorepo_inclusion     #39   +/-   ##
==============================================================
  Coverage                            6.62%   6.62%           
==============================================================
  Files                                   3       3           
  Lines                                 528     528           
  Branches                                1       1           
==============================================================
  Hits                                   35      35           
  Misses                                492     492           
  Partials                                1       1           

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[stschiff]

OK, nice, I think I'll just merge this right away, as we still have the other PR open and can have a final check then.