Drop FFTW as a dependency

[andreasnoack]

It is not used. FFTW is available under GPL, so the removal would make it easier to use this package in some projects.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.27%. Comparing base (2c52b3b) to head (2f7db77).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #105   +/-   ##
=======================================
  Coverage   95.27%   95.27%           
=======================================
  Files           8        8           
  Lines        1459     1459           
=======================================
  Hits         1390     1390           
  Misses         69       69           

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[wheeheee]

Should instead be in [extras] and [targets] I guess, those perf benchmarks still use them.

[devmotion]

How are the scripts in /perf/ supposed to be run? It seems they are only run locally? I would suggest adding an environment (Project.toml) in the /perf/ directory for benchmark specific dependencies. With the recent [sources] feature of Pkg in Julia >= 1.11, one can also easily refer to and automatically instantiate the package in the parent directory when running Pkg.instantiate() in the /perf/ directory.

[gummif]

Thanks, I think this is fine for now.

[devmotion]

Oh, great, thank you! Can you make a new release with this change?