Instead of installing the software inside slaprunner from 1.0 branch, use the
same branch as the tested one, this should allow to see regressions earlier
(before they got merged in 1.0)

In test nodes we put the software_root folder out of the webrunner so we
can keep it for the following tests. Except that the shared folder has
been introduced by default recently, and it is still inside the webrunner.

Thus, between 2 tests the webrunner is deleted, so the shared parts are too,
but not the SR folder (which is marked as completed). Then in the successive tests
the software release fails to build, or the insances fail to isntanciate.

share parts with instance-runner.cfg

/cc @rafael @Nicolas @alain.takoudjou 

/reviewed-on nexedi/slapos!527

  Allow set software-root via parameters allow the webrunner inside a erp5testnode,
  recover the the previous builds from previous resilient tests, and only update (instead build from scratch)
  This is a typical usage on the webrunner (keep updating SR), so there is no
  problem on use this approach on erp5testnode tests.

  Make the integration with erp5testnode separeted from original SR.
  Optimise KVM resilient tests by downloading the test image on the software release site,
  without change the original SR. (This will sabe internet and speed up result).

Revert "resilient: new paramater to define the time to sleep before running the backup in the cron job."

This reverts commit 30d1a937.

Default is a random value between 0 and 6 hours. KVM and Slaprunner test instances set it at 0.

Revert "slaprunner: fix resiliency test, add development-mode (bool) parameter for easy build webrunner in webrunner"

This reverts commit 59966611.

slaprunner: fix resiliency test, add development-mode (bool) parameter for easy build webrunner in webrunner

Slaprunner SR: Set resiliency-backup-periodicity parameter so that periodicity is done every  minute.