Commit ba6c3331 has a bug breaking
the ERP5 SR unless incremental catalog backups are disabled.

  Now the egg contains the missing dependency

0.4.59 has a missing dependency to 'six' and breaks too many things.

  Update the stack/slapos.cfg to use the newest version

  Remove duplicated version definition at software level to prevent excessive duplication
  of the value.

The new option will be used to fix/optimize
propagation of parameters in the NEO SR.

as datanotebook business template is now hosted there.

/reviewed-on !605

  It can be used for scalability test.

Fix nextcloud backup cron frequency
Fix apache graceful script path

this partially reverts ba52eead

Numpy version 1.16.4 was not compatible with scipy 0.19.0

Since the addition of `set -e`, several parts of the script became dead code.

This allows much better understanding for long running Kedifa processes.

also cleanup old unused versions