Refactor Ginger-Lib

[phoinic]

This PR contains the refactored algebra module and adjustments for this refactoring in other modules. The details of this refactoring are described in document "Refactoring ginger-lib". Key changes:

• Group trait is a basic trait for Fields, Polynomials and Curves
• Curve trait introduced
• Projective representation for curve points is default
• Affine representation used only for efficient mixed arithmetic and moved to the Curve trait as a nested type
• All curves removed except Tweedle and secp256k1
• All curves and fields models which are not used be Tweedle and secp256k1 are removed

Known Issues:

1. In algebra / secp256k1 unit tests there are hardcoded points in affine representation. Correct values for Jacobian representation should be placed. For now these UTs are broken and marked as ignored

2. In primitives / merkle_tree / optimized the UTs were switched from MNT curve to tweedle. The hardcoded expected output values should be updated with correct ones. For now these UTs are broken and marked as ignored

3. In proof-systems / darlin / tests inside TestCircuit there is a comment: // This calculation is wrong, as enforce_equal allocates new variables. // However, fixing this may cause unit tests to crash since num_constraints // and num_variables are generated at random and an underflow may happen. // Fix both UTs can randomly failed or pass this part with error "substract with overflow"

4. Inside r1cs / gadgets / crypto / crh / pedersen the unit-test was switched from JubJub to Tweedle. But with tweedle this UT failed for some reason. This is not a refactoring related problem because in case of changing JubJub to Tweedle inside none-refactored ginger-lib we have the same issue with this UT. For now UT is marked as ignored