feat(LinearAlgebra/QuadraticForm/Basis): Free Tensor product of Quadratic Maps

[mans0954]

WiP: Define the tensor product of two Quadratic Maps on free modules using toBilin.

It should then be possible to extend this definition to arbitrary modules using quotients.

Similar to QuadraticMap.tensorDistrib but without requiring Invertible (2 : R).

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[github-actions]

PR summary 01090d08cf

Import changes for modified files

Dependency changes

File	Base Count	Head Count	Change
Mathlib.LinearAlgebra.QuadraticForm.Basis	1373	1390	+17 (+1.24%)

Import changes for all files

Files	Import difference
Mathlib.LinearAlgebra.QuadraticForm.Basis	17

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Declarations diff

+ above_diag
+ basis_expansion
+ below_diag
+ map_finsupp_linearCombination
+ map_finsupp_sum
+ on_diag
+ polar_toQuadraticMap
+ qt_expansion
+ tensorDistriFree_polar
+ tensorDistriFree_tmul
+ tensorDistribFree
+ tensorDistribFree_apply

You can run this locally as follows

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

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

The doc-module for script/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/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).