This commit partially reverts the changes made in ec470fbe. While
the started message continues to be logged before any application and
command line runners are called, the publishing of
ApplicationReadyEvent now happens after the runners have been called.
Additionally, a new event, named ApplicationStartedEvent, has been
introduced. This new event is published after the context has been
refreshed but before any application and command line runners are
called.

Closes gh-11484

The reworking of the events described above also means that either
an ApplicationReadyEvent or an ApplicationFailedEvent will be
published and the latter should never be published once the former
has been published.

Closes gh-11485