Rename ec model files and curve struct names

[Pratyush]

Description

short_weierstrass_jacobian -> short_weierstrass
twisted_edwards_extend -> twisted_edwards
GroupAffine -> Affine
GroupProjective -> Projective
ModelParameters -> CurveConfig
SWModelParameters -> SWCurveConfig
TEModelParameters -> TECurveConfig
MontgomeryModelParameters -> MontCurveConfig

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