ISO 8601 time is useful when, say, running falco in a container, which
may have a different /etc/localtime than the host system.

A new config option time_format_iso_8601 controls whether log message
and event times are displayed in ISO 8601 in UTC or in local time. The
default is false (display times in local time).

This option is passed to logger init as well as outputs. For outputs it
eventually changes the time format field from %evt.time/%jevt.time to
%evt.time.iso8601/%jevt.time.iso8601.

Adding this field changes the falco engine version so increment it.

This depends on draios/sysdig#1317.

A unit test for ISO 8601 output ensures that both the log and event time
is in ISO 8601 format.

Now that we have an option that controls iso 8601 output, use it by
default in containers. We do this by changing the value of
time_format_iso_8601 in falco.yaml in the container.

A placeholder "N/A" is used in log messages instead.