This commit adds a general state listener to the SecurityIndexManager,
and replaces the existing health and up-to-date listeners with that. It
also moves helper methods relating to health to SecurityIndexManager
from SecurityLifecycleService.
We had a number of awaitsFix links that weren't updated after the xpack
merge.
Where possible I changed the links to the new locations, but in some
circumstances the original ticket was closed (suggesting the awaitsfix
should be removed) or was otherwise unclear the status.