[TASK] Time interval / subscription hooks

[drewstone]

Overview

Certain services might not require any onchain events to trigger their execution. Instead they may just require execution every block, or 6/12/30/60/3600 seconds, or another arbitrary event process. We should consider how this will be integrated into a job, probably using another macro argument. It should even be possible to "roll your own event listener / event triggering process". We should make the current one the default and be able to show an example in the macro of using it to roll it as if it were custom.

/// An example hook for a report that provides a incident reporting security service
pub fn report_incident(ctx: Context, ...) {
    // check on-chain state of this contract
    let contract = ctx.trap_contract;
    let incident_valid = contract.check_validity_of_trap();

    // Report the incident if there's a valid incident
    if (incident_valid) {
        contract.report_incident();
    }
}