see 2a457867 (erp5: Rework testrunner's HTTP server, 2018-09-04), with
python3 the timing is not same and sometimes the parameter was not
propagated before root partitions promise were all solved, this add a
promise at the root partition to ensure the parameter is propagated

this promise should be enabled regardless of test runner configuration

Not sure why it was OK on python2 and not sure if this has to be done
or the promise code needs to cast the results of getConfig()

Otherwise it fails with the following exception because of non-ASCII characters
(`[A-Z&é@{]{3,7})`) (see unconvert()) below):

  => erp5_core/PathTemplateItem/portal_preferences/default_site_preference.xml
     File "zodbpickle-2.0.0-py3.7-linux-x86_64.egg/zodbpickle/pickle_3.py", line 844, in load
        dispatch[key[0]](self)
     File "zodbpickle-2.0.0-py3.7-linux-x86_64.egg/zodbpickle/pickle_3.py", line 1035, in load_short_binstring
        self.append(self.decode_string(data))
     File "zodbpickle-2.0.0-py3.7-linux-x86_64.egg/zodbpickle/pickle_3.py", line 989, in decode_string
        return value.decode(self.encoding, self.errors)
  UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 19: ordinal not in range(128)

This reverts commit 6c399134.

See merge request nexedi/slapos!1383

Expose and document HTTP3 related cluster switches.

Switch to Recurls with HTTP3 enabled curl for testing.

%HU in case of HTTP/2 results with full URL being logged, while just the path
is expected in the log.

Even if the change comes from http://git.haproxy.org/?p=haproxy.git;a=commit;h=30ee1efe676e8264af16bab833c621d60a72a4d7
it has been detected since full HTTP/2 aware test client has been used.

This class mimics requests, but as an engine to access sites it uses curl
command, which is expected to be provided with a lot of features, including
full HTTP3 support.

It's fetched from the upstream repository with well known working revision.

It's very important to have readable and contextable information on failures,
in order to track root cause of the problem.

The portredir slapos.core manager won't be used in CDN deployments.

It's very usefuly to have access to such powerful tool on each CDN node, and
we shall eat our dog food anyway.

This is the only way to be assured that all expected headers are going to be
sent back to the client.

Embrace frontend name in {} and then use such "schema" to catch it during
logging. This lowers the risk of incorrect log file generation or misplaced
log lines.

In commit 547898ee
"component/openssl: Use the newest openssl with QUICTLS" there untested
upgrade to openssl-3, which has side effects with loading expired certificate
chains.

use dropdb and createdb command is a working approach to backup
restoration here