ENT-11156: Added shellcheck make target and github action workflow

[craigcomstock]

Ticket: ENT-11156
Changelog: none

[craigcomstock]

@cf-bottom jenkins

[cf-bottom]

Sure, I triggered a build:

Jenkins: https://ci.cfengine.com/job/fast-build-and-deploy-docs-master/485/

Documentation: http://buildcache.cfengine.com/packages/build-documentation-pr/jenkins-fast-build-and-deploy-docs-master-485/output/_site/

[craigcomstock]

@cf-bottom jenkins

[cf-bottom]

Sure, I triggered a build:

Jenkins: https://ci.cfengine.com/job/fast-build-and-deploy-docs-master/486/

Documentation: http://buildcache.cfengine.com/packages/build-documentation-pr/jenkins-fast-build-and-deploy-docs-master-486/output/_site/

[craigcomstock]

@cf-bottom jenkins again, I fixed perms on oslo-dc that were broken probably due to a broken trap in the shell script not cleaning up afterwards.

[cf-bottom]

Alright, I triggered a build:

Jenkins: https://ci.cfengine.com/job/fast-build-and-deploy-docs-master/487/

Documentation: http://buildcache.cfengine.com/packages/build-documentation-pr/jenkins-fast-build-and-deploy-docs-master-487/output/_site/

[craigcomstock]

@olehermanse @aleksandrychev the generated site from jenkins looks ok after poking around a dozen pages.
I made more changes to satisfy shellcheck but think this is probably solid. This is master so we can put it in right away and then cherry pick after our upcoming releases.

[olehermanse]

Thanks @craigcomstock, the changes look reasonable / safe.

[craigcomstock]

maybe cherry pick AFTER the release 👍

[craigcomstock]

cherry picks, why not... we have the final tag now. 👍

#3195
#3194