Function initialize 

pub fn initialize(
    initializer: &Pubkey,
    admin: Pubkey,
    mint_fee_lamports: u64,
    allocation_fee_per_recipient_lamports: u64,
    merkle_fee_per_recipient_lamports: u64,
    direct_transfer_fee_per_recipient_lamports: u64,
) -> Result<Instruction, ProgramError>

Create an instruction to initialize the program