Add multi-range check to assertAlmostReduced

[MartinMinkov]

Summary

Addressing an issue with EcsdaSignature and ForeignCurve overriding check() to use assertAlmostReduced. This skips the option to multi-range check all the input variables, which can lead to passing assertions if a malicious prover wishes to do so.

Changes

• Added a range check on inputs within the check functions of EcdsaSignature and ForeignCurve
• Update the regression verification key artifacts

[mitschabaude]

@MartinMinkov the change looks good to me now, but it's breaking and we should ship it in a backwards-compatible way. check() is called internally just by using the overall class as method input. So it's the class that we have to create an alternative version for.

How about this:

• Leave ForeignCurve class untouched
• New ForeignCurveV2 which extends ForeignCurve and just overrides the check() method
• new createForeignCurveV2() which is exactly like createForeignCurve() but uses ForeignCurveV2
• deprecate createForeignCurve(), move doccomments over to createForeignCurveV2()

And same for EcdsaSignature!

[mitschabaude]

Perfect!