This functionality allows a stage to be uploaded and validated as
normal, but not activated. This is useful to pre-flight an Icinga config
package before it is applied to a monitoring cluster, for example in a
CI pipeline.
This means a new timer which checks every 5m whether the
active-stage can be read, and if not, it overwrites the
file on disk with the details from memory.
You can now specify a boolean `reload` attribute that
will allow you to skip the icinga2 reload after config
validation. By default this is set to true.
The response text has been updated to show if icinga2
will reload or if it was requested to be skipped.
fixes#4769