e0b627ea81 deserialize witness from a list of hex strings - ci(primitives): enable hex feature in CI build - from_hex() implemented more efficiently (aagbotemi)
Pull request description:
This PR implements `from_hex` function for deserialize `Witness` from a list of hex strings. Added unit test.
This PR fixes#4350
ACKs for top commit:
apoelstra:
ACK e0b627ea816a730949cdb200105598600fcac094; successfully ran local tests
tcharding:
ACK e0b627ea81
Tree-SHA512: deec3f9e5f67a0915b11a811c40c341dd9f24d0394d6cfbd6a09f765ce3fc0dcce2740949c264d4aa2d2db748a5ce81416b4dac15b1b64475a7c024b205e40ab