Add exponential backoff for network-related calls

[Martchus]

See https://progress.opensuse.org/issues/133349

[Martchus]

I've tested this locally with some dummy command that would fail. Note that the short form (e.g. -es 30 instead of -e -s 30) does not work:

$ retry -es 3 -- bash -c 'echo foo && exit 1'
/usr/bin/retry: Zeile 38: 3: Kommando nicht gefunden.
Retrying up to 3 more times after sleeping 3s …
/usr/bin/retry: Zeile 38: 3: Kommando nicht gefunden.
Retrying up to 2 more times after sleeping 0s …
/usr/bin/retry: Zeile 38: 3: Kommando nicht gefunden.
Retrying up to 1 more times after sleeping 0s …
/usr/bin/retry: Zeile 38: 3: Kommando nicht gefunden.

Maybe that's something we want to fix within the retry script?

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏

[perlpunk]

https://openqa.opensuse.org/tests/3492023#step/test_distribution/3 (problem with Test::Assert) will be fixed soon, see https://bugzilla.opensuse.org/show_bug.cgi?id=1214057
https://openqa.opensuse.org/tests/3492019#step/openqa_webui/13 (problem with Class::Accessor) - I'll have a look

edit: tracked here now: https://progress.opensuse.org/issues/133979