feat(ContinuousFunctionalCalculus): add integral representation for x ↦ x ^ p for p ∈ (1, 2)

[dupuisf]

This PR adds an integral representation for the function x ↦ x ^ p for p ∈ (1, 2). We already have an analogous representation for p ∈ (0, 1). This will later be used to show that this function is operator convex in that range.

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[github-actions]

PR summary 8850ed9386

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

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Declarations diff

+ continuousOn_rpowIntegrand₁₂_uncurry
+ exists_measure_nnrpow_eq_integral_cfcₙ_rpowIntegrand₁₂
+ exists_measure_rpow_eq_integral_rpowIntegrand₀₁
+ exists_measure_rpow_eq_integral_rpowIntegrand₁₂
+ integrableOn_rpowIntegrand₁₂
+ monotoneOn_rpowIntegrand₁₂
+ rpowIntegrand₁₂
+ rpowIntegrand₁₂_eq_mul_rpowIntegrand₀₁
+ rpowIntegrand₁₂_nonneg
+ rpowIntegrand₁₂_zero
+ rpow_eq_const_mul_integral_rpowIntegrand₁₂

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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Increase in tech debt: (relative, absolute) = (1.00, 0.00)

Current number	Change	Type
6909	1	backward.isDefEq.respectTransparency

Current commit 847712d46a
Reference commit 8850ed9386

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).

[github-actions]

✅ PR Title Formatted Correctly

The title of this PR has been updated to match our commit style conventions.
Thank you!

[mathlib-merge-conflicts]

This pull request has conflicts, please merge master and resolve them.