* feat: AzureMonitor implements legend key on backend

To be able to remove the duplicated query logic on the
frontend, the backend code needs to implement alias
patterns for legend keys as well as allowing the default
list of allowed time grains to be overridden. Some metrics
do not support all the time grains and the auto timegrain
calculation can be incorrect if the list is not overridden.

* feat: AzureMonitor - removes duplicate query logic on frontend

* AzureMonitor small refactoring

Extracted method and tidied up the auto time grain
code.

* azuremonitor: support for auto time grains for alerting

Converts allowed timegrains into ms and saves in dashboard json.
This makes queries for alerting with an auto time grain work in
the same way as the frontend.

* chore: typings -> implicitAny count down to 3413

* azuremonitor: add more typings