Serialization for BigInts is redefined to be in base 10 instead of 16

[vnermolaev]

I noticed that the crate redefines serialization of curv::BigInts to be in base 10, e.g.,

for KeyPair, p and q are going to be in base 10

rust-paillier/src/lib.rs

Lines 23 to 29 in 7d4958f

	pub struct Keypair {
	#[serde(with = "crate::serialize::bigint")]
	pub p: BigInt, // TODO[Morten] okay to make non-public?
	#[serde(with = "crate::serialize::bigint")]
	pub q: BigInt, // TODO[Morten] okay to make non-public?
	}

because

rust-paillier/src/serialize.rs

Lines 9 to 11 in 7d4958f

	pub fn serialize<S: ser::Serializer>(x: &BigInt, serializer: S) -> Result<S::Ok, S::Error> {
	serializer.serialize_str(&x.to_str_radix(10))
	}

while in the curv crate BigInts are serialized using base 16

https://github.com/ZenGo-X/curv/blob/78cac40a47e145eb845d687cc748f9312d999db9/src/arithmetic/serde_support.rs#L9-L21

Imagine a server defines a struct as such

#[derive(Serialize, Deserialize)]
struct S {
  b: curv::BigInt,
  ek: EncryptionKey
 } 

then a third-party app needs to selectively serialize BigInts of the corresponding fields.

What was the reason behind that?