[feat]: derive implementation of Rust SDK for program instructions

At this point we code helper methods to create instructions for our programs.

Here is an example:

pub fn approve_use_authority(
    program_id: Pubkey,
    use_authority_record: Pubkey,
    user: Pubkey,
    owner: Pubkey,
    payer: Pubkey,
    owner_token_account: Pubkey,
    metadata: Pubkey,
    mint: Pubkey,
    burner: Pubkey,
    number_of_uses: u64,
) -> Instruction {
    Instruction {
        program_id,
        accounts: vec![
            AccountMeta::new(use_authority_record, false),
            AccountMeta::new(owner, true),
            AccountMeta::new(payer, true),
            AccountMeta::new_readonly(user, false),
            AccountMeta::new(owner_token_account, false),
            AccountMeta::new_readonly(metadata, false),
            AccountMeta::new_readonly(mint, false),
            AccountMeta::new_readonly(burner, false),
            AccountMeta::new_readonly(spl_token::id(), false),
            AccountMeta::new_readonly(solana_program::system_program::id(), false),
            AccountMeta::new_readonly(sysvar::rent::id(), false),
        ],
        data: MetadataInstruction::ApproveUseAuthority(ApproveUseAuthorityArgs { number_of_uses })
            .try_to_vec()
            .unwrap(),
    }
}

However they could be generated in a similar way that solita does generate as part of the TypeScript SDK.

For now I'm thinking it is easier to do this via impl derived from the Instruction enum (annotated with shank), but will solidify these implementation details once we start work on this.

metaplex-foundation / shank

[feat]: derive implementation of Rust SDK for program instructions #19