msg cycles available

This section is a work in progress.

Examples:

import { Canister, ic, nat64, update } from 'azle/experimental';

export default Canister({
    // Moves all transferred cycles to the canister
    receiveCycles: update([], nat64, () => {
        return ic.msgCyclesAccept(ic.msgCyclesAvailable() / 2n);
    })
});