Set instance size to 0 for more z2 jobs

  In order to reduce nb of vms in cf-minimal-dev.yml
Updates to allow crash_lifetime_secs be configurable.
Merge pull request #290 from Orange-OpenSource/smaller-min-dev

Set instance size to 0 for more z2 jobs
Merge pull request #291 from DanLavine/configure_dea_crash_lifetime

Updates to allow crash_lifetime_secs be configurable.