README: Remove AzManagers.jl for now

[DilumAluthge]

AzManagers pirates the Distributed.addprocs(vmtemplate, n) method. See ChevronETC/AzManagers.jl#176

We probably shouldn't list this package in the README until the piracy is fixed.

Once the piracy is fixed, we can add the package back to the README.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 25.40%. Comparing base (9dad53c) to head (ab0251e).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #263   +/-   ##
=======================================
  Coverage   25.40%   25.40%           
=======================================
  Files           6        6           
  Lines         307      307           
=======================================
  Hits           78       78           
  Misses        229      229           

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