this was just not tested

After upgrade to OpensSSH 8.8p1 the simple ssh-rsa keys are not accepted
anymore.

This is based on commit "Firefox Version Up to 78.1.0esr", but it does not
replace the default firefox, just enable a new version for now.

Several softwares were using fixed versions, but versions are also defined in
stack/slapos.cfg, so let's use from stack/slapos.cfg which will simplify
version management.

This urllib3 has visible changes for us, it no longer send the request path
"as is", but normalizes the . and .. which is not what we want in
caddy-frontend test, so we adjust the test to use prepared requests, which is
the recommended approach for this kind of low level needs. Since prepared
requests does not set default user agent "python-requests", tests checking that
user agent is in log files have been adjusted to use a dedicated test user agent
header.

Another change is that certificates are now verified by default, so we adjust
seleniumserver tests to disable certificate validation. jstestnode, already
had a patch regarding certificate validation, because we wanted certificates
to be validated before it was the default. We just update this patch a bit
because we want to keep the optional behaviours of validating against a
specific CA or to disable validation.

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

This test was just checking the data from the first recv call, but the
data might arrive in multiple times. Call recv in a loop until we
received the end of the expected message (or until timeout when
something goes wrong).

so that on first connection clients can check the fingerprint key
instead of blindly accepting it.

This seem to be needed "sometimes", apparently on the first connection
after server is started, but this was not investigated much.

seleniumrunner software recently became a full selenium server, which is
different from the original software, that was only intended as being a
minimal software to make firefox available for erp5testnode.

This caused several problems in erp5testnode, because erp5testnode needs
to be always able to build seleniumrunner from master branch (which is
probably wrong in the first place). With this software having lots of
components, the risk of build problems increased.

Also, it's something else, so let's make it another software.

Software just to in install a test runner