Remove Response using Adjacently tag

[whylee259]

It seems for us to be able to use the Adjacently tag and the deserializer of derive

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I wonder why this uses a manually implemented deserializer rather than use derive as follows.

#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
#[serde(untagged)]
pub enum Token {
    FT(FungibleToken),
    NFT(NonFungibleToken),
}

Additionally, using Adjacently tag, seems to be able to reduce the depth of response struct.

#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
#[serde(tag = "type", content = "value")]
pub enum Token {
    #[serde(rename = "collection/FT")]
    FT(FungibleToken),
    #[serde(rename = "collection/NFT")]
    NFT(NonFungibleToken),
}

let res = serde_json::from_str::<Vec<Token>>(json);

but we can discuss reducing depth on another issue.

Originally posted by @whylee259 in #35 (comment)