docs: Alternative links to web archives added to external links

fixup! docs(README): mirror and contribute information added, 'reuse' badge link changed to sr.ht, archive links added to external links

docs(README): mirror and contribute information added, 'reuse' badge link changed to sr.ht, archive links added to external links

docs(README): minor improvements, missing entries added to ToC, additional information about /dev/shm and sapconf package added

docs: RHEL7 to Table of Content added

fix: information about ubi7 relation added

docs(sles12sp5-python2-systemd): information about suse subscription requirements added, typos corrected

docs(sles12sp5-python2): information about suse subscription requirements added, typos corrected

docs(rhel7-python2-systemd): information about ubi7 relation added, typos corrected

docs: Information about RHEL7 Container added

fix(rhel7-python2-systemd): openssh client instead server package added

fix(sles12sp5-python2-systemd): unncessary rm command remove from run statement

fix(sles12sp5-python2-systemd): typo in libaudit package name

feat(sles12sp5-python2-systemd): audit packages added

feat(rhel7-python2-systemd): audit packages added

docs: README for rhel7-python2-systemd

feat: rhel7/ubi container with systemd and python

feat(sles12sp5-python2-systemd): rsyslog and openssh added

docs: License Section and Reuse Badge added to README

docs: spdx compliant license header information added to Dockerfiles