Several bug fixes

use correct python-cryptography package

Use python-cryptography on EL7 - use python-cryptography3 everywhere
else
https://bugzilla.redhat.com/show_bug.cgi?id=1989962

[FIX] README false variable name

inside role rsyslog logging_purge_original_conf variable is named logging_purge_confs

python2 renders server_host list incorrectly

On python2 (el7) when server_host is a list, this:

            server={{ item.server_host }}

gets rendered as this:

            server=[u'logging-es0', u'logging-es1']

I think we should not rely on the python/jinja2 list to string conversion
being exactly the same format as the rsyslog string list format.

do not warn about unarchive or leading slashes

https://bugzilla.redhat.com/show_bug.cgi?id=1984182
Use the args.warn: false to omit the warning about using
unarchive instead of the tar command.
Use the tar -P flag to omit the warning about trimming
leading slashes / from the paths.