Instead of having to copy and paste the "ssh command", having a
clickable link is more user friendly. This integrates seamlessly with
ChromeOS secure shell app (eventhough the app does not do anything with
fingerprint as per version 0.19)

Because this slapos often is executed when just running `slapos` at is
in the $PATH, we should also consider special cases where users want to
call this script with another $SLAPOS_CONFIGURATION.

When $SLAPOS_CONFIGURATION is already set, ~/bin/slapos will not change
it, it will only set it when not set.

Because slaprunner might be instanciated in a different directory than
the shell user $HOME (like in recursive SlapOS), it's necessary to set
HOME to the base directory. For "bare metal" SlapOS, this would not make
any difference.

so that terminal uses terminfo from the same curses library.

Also change download URL to use https:// (no reason to use http)
Also switch to git format patch

this is the firefox we are currently using on testnodes. It's useful to
be able to run test with exactly same version to debug issues.

/reviewed-on nexedi/slapos!646

Nextcloud's redis is causing `AF_UNIX path too long` on test nodes.

The first commit to adapt this test to slapos.testing was incomplete.
Now that nextcloud is fixed, we saw a few mistakes and python3
incompatibilities that are fixed in this commit.

This reverts commit 4636f49f.

This reverts commit 97884c30.

Package like lm-sensors, which depends on the kernel, shall be provided
by the OS.

/reviewed-on nexedi/slapos!642

It is proven to work on Debian 10.

/reviewed-on nexedi/slapos!640

slapos node collect require lmsensors, so use those ones provied with slapos
component.

/reviewed-on nexedi/slapos!641

Otherwise it will be installed without our special part, using system
curl.

/reviewed-on nexedi/slapos!639

/reviewed-on nexedi/slapos!635

also drop test_nextcloud_promises as promises are now checked by
framework.

/reviewed-on nexedi/slapos!636

Prove that:

 * VNC is accessible
 * monitor-base-url on each partition is accessible with password extracted
   from the main partition

frontend-instance-guid and frontend-additional-instance-guid are used to
control where the websocket frontend shall end up.

Real frontend is always requested.

Additional frontend is requested only if frontend-additional-instance-guid is
not empty. This frontend is published as url-additional and can be used for
access to users from some restricted networks.

publish-early does not work in this case, and monitor password is stored
in buildout elsewhere anyway.

Update almost all tests to use nexedi/slapos.core!64 

Notable changes:
 * the testcase class is generated dynamically with `makeModuleSetUpAndTestCaseClass`
 * `self.slap` allow low level control of slapos
 * IP addresses are available as `_ipv6_address` and `_ipv4_address` class attributes
 * `getSupervisorRPCServer` no longer exist, instead use `self.slap.instance_supervisor_rpc` (as context manager)
 * now the framework takes care of running promises and instance step fail when instanciation fail or when promises are not satisfied (as a result, some tests checking promises are dropped)
 * test needs `slapos` and `supervisord` commands in PATH. It's important to have a recent enough `slapos` and not the `~/bin/slapos` from slaprunner which sets `$SLAPOS_CONFIGURATION` 

Following tests were not updated:
 * `caddy-frontend` as this will require more work, because this software uses shared partitions and maybe other things will need to be adapted in the tests. 
 * `slapos-master` as it is same as ERP5 and I thought maybe we can do better than duplicating code, so I left it as is for now.
 * `nextcloud` as this fail the `slapos node instance` step.

There are also a few style changes or small fixes to make pylint happy and some other fixes for problems with softwares and also a fix for seleniumrunner flaky test.

/reviewed-on nexedi/slapos!624

also drop test_turnserver_promises as promises are now checked by
framework.