(IAC-563) Release Merge back v3.0.0

pdksync - (maint) - Pdk Update

Perform a PDK update to commit the following changes:
- Add Litmus dependencies
- Remove Beaker dependencies
- Ensure CI tests run in serial mode instead of parallel (spec)

Also add support for new platforms to metadata.json

There was a significant refactor in the test behaviour for Linux
systems as part of the port to Litmus. Windows remains largely
unchanged.

For Linux systems, we significantly increased the platforms we're
testing against to more accurately reflect the module's compatible
OSs. Relying on 'shutdown -c' was not possible anymore:
- systemd based OSs create /run/nologon when shutdown is invoked,
preventing any more logins during the test
- On modern OSs, 'shutdown -c' cannot cancel the reboot operation
in anywhere near quick enough a manner
- 'shutdown -c' will return 0 even if a shutdown operation was NOT
in progress
- 'shutdown -c' did not have consistent stdout / stderr messages
to validate against. Typically, shutdown is a symlink to another
binary / script, so behaviour differed between OSs quite sigificantly.

The new approach is to substitute the shutdown cmd on PATH with a
script that will output the args it was called with to a log file.
We will then verify the correct args were passed to the script.
This allows us to execute the agent with the module on each platform
and ensure that functionality such as subscribing to another resource
or invoking another resource downstream of a reboot, still works as
expected.

We will take a backup of the shutdown bin / script and restore it
after the test suite has executed. There is also logic to ensure
that we do not overwrite this binary if our dummy script is still
present (this handles the scenario where a test is interrupted and
then resumed before the RSpec.after block has executed).

Ensure the spec_prep Rake task runs before any Litmus Rake tasks
as the Bolt tasks require them.

Helper method added to process Bolt task output for test pass/fail
assertion.

Changed Bolt version dependency from '~> 1.3' to '> 1.3' as we're
on 2.x now.

(IAC-140) Port puppetlabs-reboot to Litmus

pdksync - Add dependency gems to development group

(IAC-140) Add ed25519 gem to Gemfile

(IAC-140) Add ed25519 gem to system_tests gem group

Run pdk update

Fix Rubocop offence

(IAC-140) Litmus port cleanup

pdksync - Use abs instead of vmpooler to provision test resources

pdksync - (IAC-886) Back out SLES 11 from release checks

pdksync - (IAC-890) - Implement CentOS 8 travis tests

pdksync - (IAC-973) - Update travis/appveyor to run on new default branch `main`

…uthorname

(IAC-1116) - updating authorname to puppetlabs

Removal of any offensive or inappropriate terminology from the code base.

…ppropriate_terminology

(IAC-1003) - Removal of inappropriate terminology