feat(Probability/Kernel): define IsDeterministicKernel

[gaetanserre]

Defines the IsDeterministicKernel typeclass which state that a kernel is deterministic in a categorical sense, i.e., it "commutes" with Kernel.copy.

For some additional context, please see #37851.

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[github-actions]

PR summary 896cc56a39

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference
Mathlib.Probability.Kernel.Deterministic (new file)	1592

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Declarations diff

+ IsDeterministicKernel
+ IsZeroOneMeasure
+ Measure.zero_one
+ comp_natural
+ compl_eq_zero
+ copy_comp_apply_prod
+ deterministic_is_deterministic
+ exists_one_iff_univ_one
+ instance : IsDeterministicKernel (Kernel.id (α := α))
+ instance : IsFiniteMeasure μ
+ inter_eq_one
+ inter_eq_prod
+ is_deterministic_iff_zero_one
+ parallelComp_id_comp_copy_comp
+ univ_one
+ zero_one

You can run this locally as follows

## summary with just the declaration names:
./scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh contains some details about this script.

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No changes to technical debt.

You can run this locally as

./scripts/reporting/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).