Fix export.py

[growly]

• Export script would produce duplicate modules, one copy with parameters and one without. No longer.
• File header comment now passably useful.
• PDK name used for export now comes from pdk_data.py.
• Script itself moved to ../scripts directory.

[codecov[bot]]

Codecov Report

Merging #169 (f61bc0c) into main (5c0daad) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #169   +/-   ##
=======================================
  Coverage   87.20%   87.20%           
=======================================
  Files         109      109           
  Lines        9577     9577           
=======================================
  Hits         8352     8352           
  Misses       1225     1225           

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[growly]

I'm pretty sure the failing dev tests are exclusively due to the changes to Vlsir protos upstream, and are fixed by #172

[dan-fritchman]

This ready to merge?