Payment solution field added to program and instance

[leirbag95]

Here is what I changed:

/**
 * Code to execute
 */
export type CodeContent = {
    encoding: Encoding;
    entrypoint: string;
    ref: string;
    use_latest: boolean;
    interface: string;
    args: string[];
};
...
/**
 * Payment solution
 */
export type Payment = {
    chain: Chain;
    receiver: string;
    type: PaymentType;
};

export type ProgramContent = BaseContent & {
    ...
    payment?: Payment;
};

aleph-im/aleph-message@92ad3e4

content of INSTACE/PROGRAM:
{
"code" : {
+ "interface": str,
+ "args": str[],
...
}

• "payment" : {
• "chain": str,
• "receiver": str,
• "type": "hold" | "superfluid"
• }
  }

https://community.aleph.im/t/pay-as-you-go-using-superfluid/98/12

https://docs.superfluid.finance/superfluid/developers/constant-flow-agreement-cfa/cfa-operations/write-methods/createflow

[MHHukiewitz]

ProgramContent and InstanceContent have some overlap, try to merge them in one BaseExecutableContent and expand on that type

[MHHukiewitz]

Finally, all types clean in the types folder. LGTM