This PR aims to implement some changes that ensure no malformed commands
are passed through to the system. Certain commands were left undivided
as the commands did not get correctly interpreted.

Primarily, the commands targeted were the ones related to Open3 and exec.

Prior to this commit lint would not work properly in Github Actions.

This commit aims to fix the problems that cause failure in CI.

Prior to this commit, there was a block of code checking for puppet 5,
which we no longer support.

This commit aims to clean up this unnecesary code in order to keep the
module tidy.

(maint) Hardening manifests and tasks

Ruby Shellwords#shellescape "Escapes a string so that it can be safely
used in a Bourne shell command line".  This is fine for a UNIX like
operating system, but windows does not complies with this.

Attempt to fix CI by manually "escaping" strings on windows (i.e. quote
them and escape quotes with a backslash), and relying on shellescape for
other operating systems.

At the cost of one more function call, we gain in readability and what
the docker::escape functions is more straightforward.

Escaped strings should not be quotted.

While here, also rework the way networks are escaped: the previous code
was generating invalid parameters.

docker_run_flags: Shellescape any provided values

Prior to this commit, as part of the codebase hardening project, an
important piece of update was missed: raising the minimum required
puppet version to 6.24.0, so that certain command breakdowns could
occur.

This commit aims to fix that. It can also be considered part of the
ticket CONT-263 and the final update required before a major release can
be cut.

…sion_bump

(CONT-263) Bumping required puppet version

Release prep v6.0.0