Follow-up from #399 and #400 and last breakage of internal APIs, at least for a while ...

This does not break code that depends on public protocols like BLS signatures, KZG commitments or EVM precompiles.
It will break code that imports internals.

Changes:

• Rename C: static Curve to Name: static Algebra. It would be weird to support Stark primes like M32, Babybear or Goldilocks with "Curve".
• Functions to access field properties that used the curve say BLS12_381 have been replaced by functions that use the field Fp[BLS12_381], Fr[BLS12_381] instead.
  • getCurveBitwidth and getCurveOrderBitwidth replaced by Fp[BLS12_381].bits() and Fr[BLS12_381].bits()
  • Mod, getCurveOrder and fieldMod replaced by modulus
• Shorter type names:
  • ECP_ShortW -> EC_ShortW (originally ECP == Elliptic Curve Point)
  • ECP_TwEdwards -> EC_TwEdw
• EC Mixed Addition: madd renamed to mixedSum, msub to mixedDiff
• low-level exports renamed and splits from curves_primitives to lowlevel_*