the IMT settings already contains slapos master urls

This reverts commit 8fdf3f1a.

It's all the more important as OpenVPN tarballs can't be downloaded with
default Python user-agent.

`slapos.libnetworkcache` depends itself on `setuptools`.

/reviewed-on !88

INSTALL_PREFIX has been deprecated in openssl so it was renamed to DESTDIR and uses the
new `make-install-extra` option added here:  slapos!524

/cc @tomo @jm 

/reviewed-on !87

/reviewed-on !86

Useful for unstable connection to some (distant) servers, also the package is available on chromebrew too.

PS: The package seems also to be available in almost all Linux distributions: https://pkgs.org/download/mosh

/reviewed-on !85

Hello @alain.takoudjou for my on-call duty which starts soon, please merge my ssh key and update all the machines.

/reviewed-on nexedi/slapos.package!84

/cc @jm @rafael 

/reviewed-on nexedi/slapos.package!83

this is needed for all servers hosting VMs. As we don't really know which server are hosting VM, we do it on all vifib servers.

/cc @alain.takoudjou @rafael @guillaume.hervier

/reviewed-on !82

This will be useful to setup machines where we already have IPv6 (for example, VM with IPv6 coming from the host).

/cc @alain.takoudjou @guillaume.hervier @rafael

/reviewed-on nexedi/slapos.package!81

This will be useful to setup machines where we already have IPv6 (for
example, VM with IPv6 coming from the host).

As slapos is started by cron, this number will reach the default limit very fast

/reviewed-on nexedi/slapos.package!80

/cc @alain.takoudjou @rafael

/reviewed-on nexedi/slapos.package!79

  This release is same as 1.0.83.1 with the update of slapos.core

  Reference for the latest released package.

This reverts commit b598acb4

/reviewed-on !76