feat: PhyslibAlpha/QuantumMechanics: operators on one coordinate of a product of finite targets

[naype888-cloud]

hellow guys joseph, timeroot im here agaín whit a short one PR, what this PR does? it's easy Adds "PhyslibAlpha/QuantumMechanics/HilbertSpaces/FiniteTarget/Product.lean". A system whose config, are pairs (a,b) has the Hilbert Space H (alpha * betha) an operator A on H (alpha) acts on the first coordenate alone, (A * psy) (a,b) = (sumatory) a', (a|A|a') * psy ( a' , b ), and leaves the second one in place, likewhise for H(betha) .

1.- "onFst", "OnSnd": an operator acting on one coordenate
2.-"onFst_comp", "on_Snd_comp": acting twice on the coordenate composes the operators.
3.- "onFst_comp_onSnd": operators on diferent coodenate conmute's
4.-"onFst_isSymetric", "onSnd_isSymetric":hermitian operators, stay hermitian.
this one PR it's an independent one "Physlib.QuantumMechanics.HilbertSpaces.FiniteTarget.Basic"

tks alot, have a nice day guys, im waiting for the review and happy to make any changes¡

[github-actions]

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[jstoobysmith]

Approved. Will merge shortly