[#5727] OpenSSL August 2021 patches.

[dumol]

Scope

Update python-package with the latest OpenSSL security updates from OpenSSL 1.1.1l. More at ​https://www.openssl.org/news/vulnerabilities.html.

Also update OpenSSL 1.0.2 sources for the AIX package using the updated source package for Ubuntu Server 16.04.

In the end, still build the x86 Windows package, to have it ready in case we need it again in server. Therefore, the related brink.sh change in server repo was not backported here.

Changes

Done the above. OpenSSL 1.0.2 patches for CVE-2021-3712 applied from https://launchpad.net/ubuntu/+source/openssl1.0/1.0.2n-1ubuntu5.7.

AIX packages were built manually on both Eliseni's WPAR and an IBM Cloud VM generated from my "python-package" saved image. At https://bin.chevah.com:20443/testing/2.7.18.13fe715/, I've uploaded the one from Eliseni as it has an older 7.1 TL (technology level) version: 7100-02 vs 7100-05.

Drive-by changes:

• Updated cffi and wheel to the latest versions.
• Back to using Start-BitsTransfer on Windows with SFTPPlus 4.13.
• Minor Docker optimizations for faster builds.

How to try and test the changes

reviewers: @adiroiban

To review changes:

git diff master .github chevah_build python-modules/chevah-python-test/

To test with server: https://github.com/chevah/server/pull/1855

[dumol]

needs-review

[adiroiban]

Nice work. Thanks!