refactor(RSSHandlerRoutine): switch to Instant

[christolis]

From a recent conversation:

[13:09]Zabuzard: while at it, ZonedDateTime should be replaced by Instant in that file
[13:10]Zabuzard: does someone want to tackle that quickly or else we need to make a github issue 🙂
[13:56]christolis: what makes this change worthwhile?
[14:01]Zabuzard: its just the wrong class for the job
[14:01]Zabuzard: there is no reason to use ZDT in this case
[14:01]Zabuzard: Instant is the correct class
[14:02]Zabuzard: shouldnt require any deeper changes in this case, just a quick replacement should work```

[tj-wazei]

Looks reasonable to me.

[ankitsmt211]

this will throw java.time.format.DateTimeParseException, we should handle it instead of just silenty eating the exception. Something like

catch (DateTimeParseException ignored) {
        try {
            //TODO: Should be removed once we cycle through all stored ZDT string instances
            Instant parsed_instant = ZonedDateTime.parse(raw).toInstant();
            //INFO log here converted from raw -> instant
            // save parsed_instant to database so this doesnt trigger exception on next run
            return Optional.of(parsed_instant); //
        } catch (DateTimeParseException e) {
            return Optional.empty();
        }
    }
    

[ankitsmt211]

everything looks good but we should handle the outdated timestamps stored in DB