Add Enzyme compatibility

[sethaxen]

This PR adds enzyme compatibility by marking as inactivate using EnzymeRules the numerical methods used only for control flow.

Since Enzyme supports mutation, a future PR could add mutating variants of expv and expv_sequence, which should then just work with Enzyme.

To test this using our current suite, an Enzyme backend needs to bee added to AbstractDifferentiation.

[codecov[bot]]

Codecov Report

Merging #22 (da69879) into main (1adb569) will decrease coverage by 2.47%. The diff coverage is 0.00%.

@@             Coverage Diff             @@
##              main      #22      +/-   ##
===========================================
- Coverage   100.00%   97.53%   -2.47%     
===========================================
  Files            6        7       +1     
  Lines          158      162       +4     
===========================================
  Hits           158      158              
- Misses           0        4       +4     

Impacted Files	Coverage Δ
ext/ExponentialActionEnzymeCoreExt.jl	0.00% <0.00%> (ø)

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