ctx.periodStart and ctx.PeriodEnd not enough to set proper kibana dashboard urls

[niclasgeiger]

Hey!
I am currently trying to implement proper links to our kibana dashboards in our alerting messages for our devs, so they dont have to look up the alerts themselves.
One problem I am facing so far is the following:

1. We have monitors that check e.g. every 5 minutes for all Warnings that popped up in the last 30 minutes. If I am using ctx.periodStart and ctx.PeriodEnd this is just set to the 5 minute interval.
   Is there any other way to circumvent this? To my knowledge e.g. mustache does not support date operations in the message templating, as I would otherwise just set the start time to ctx.PeriodEnd - 30m?
2. For monitors that are triggered via schedules and not periods, I don't find any way to actually reference the timeframe for those monitors in my message template as periodStart and end will not reflect a monitor that is e.g. triggered once a day.

I would be really glad to any advice on how to still do this or someone pointing me into a direction where I could create a PR here.