Add encrypted XOR support

[cgouert]

Needs to be added to compiler and functional units generated for all libraries except SEAL and TFHE.

[jimouris]

XOR is supported only for binary encodings.

• [x] SEAL:

  std::vector<seal::Ciphertext> xor_bin(seal::Evaluator& evaluator, seal::RelinKeys& relinKeys,
  std::vector<seal::Ciphertext>& ctxt_1, std::vector<seal::Ciphertext>& ctxt_2, size_t ptxt_mod) ;

• [x] PALISADE:

  template <typename T>
  std::vector<Ciphertext<T>> xor_bin(CryptoContext<T>& cc, std::vector<Ciphertext<T>>& c1,
  std::vector<Ciphertext<T>>& c2, size_t ptxt_mod)

• [x] TFHE:

  void e_xor(std::vector<LweSample*>& result, const std::vector<LweSample*>& a,
                const std::vector<LweSample*>& b, const size_t nb_bits,
                const TFheGateBootstrappingCloudKeySet* bk);

• [x] Lattigo:

  func BinXor(c1, c2 []*bfv.Ciphertext) []*bfv.Ciphertext

• [x] HElib

  std::vector<helib::Ctxt> xor_bin(helib::PubKey& public_key, std::vector<helib::Ctxt>& ct1_, 
  std::vector<helib::Ctxt>& ct2_, size_t ptxt_mod);