enforce optimize as an "auxiliary" module

[andrijapau]

Context:

The goal of this PR is to isolate the optimize module as an auxiliary module.

Description of the Change:

• Removes all top-level imports, import pennylane as qml from this module.
• Define it to be an auxiliary module in the tach.toml
• Ignore the fact that optimize (auxiliary), depends on fourier (tertiary) using # tach-ignore ([sc-89244])
• Cleans up useless pylint disables.

Benefits: Module dependency enforcement

Possible Drawbacks: N/A

[sc-88817]

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.64%. Comparing base (d9a21b6) to head (8a1d240).
Report is 1 commits behind head on fix-gradients-dep.

Additional details and impacted files

@@                Coverage Diff                 @@
##           fix-gradients-dep    #7262   +/-   ##
==================================================
  Coverage              99.64%   99.64%           
==================================================
  Files                    512      512           
  Lines                  50198    50220   +22     
==================================================
+ Hits                   50020    50042   +22     
  Misses                   178      178           

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