feat: add syscalls using Barreto-Naehrig (BN) curve construction

[Flouse]

Add BN syscalls

/**
 * @param input  two curve points (x, y)
 * @param output curve point x + y, where + is point addition on the elliptic
 * curve
 *
 * Fails on invalid input
 */
typedef int (*gw_bn_add)(const uint8_t *input, const size_t input_size,
                         uint8_t *output);

/**
 * @param Input  two curve points (x, y)
 * @param output curve point s * x, where * is the scalar multiplication on the
 * elliptic curve
 *
 * Fails on invalid input
 */
typedef int (*gw_bn_mul)(const uint8_t *input, const size_t input_size,
                         uint8_t *output);

/**
 * @param input  Input: (a1, b1, a2, b2, ..., ak, bk) from (G_1 x G_2)^k
 *               Note that k is the input_size divided by 192
 * @param output curve point s * x, where * is the scalar multiplication on the
 * elliptic curve
 *
 * @return Empty input is valid and results in returning one.
 *
 * Fails on:
 *   1. the input_size is not a multiple of 192
 *   2. any of the inputs are not elements of the respective group are not
 * encoded correctly
 */
typedef int (*gw_bn_pairing)(const uint8_t *input, const size_t input_size,
                             uint8_t *output);