(maint) bump to beaker 4

This commit updates the configuration file to point to the official Puppet VS Code Extension `puppet.puppet-vscode`

(maint) Update Puppet VS Code Extension ID

In preparation for the Puppet 7 release, the
`puppet-module-posix-dev-r2.7` and `puppet-module-posix-dev-r2.7` gems
had to be removed from `Gemfile` due to the following dependency error:
  `puppet-module-posix-dev-r2.7` depends on
    `puppet_litmus` which depends on
      `bolt` which depends on
        `puppet` which is locked to a version below 7

Also added the needed gems that were lost in the above removal process.

Added GitHub Actions workflows for `Static Code Analysis` and `Unit
Tests` that run each time there is a new `pull request` or `git push`.
`Unit tests` are also set to run every workday at `05:00:00 UTC`.

The `.yaml` config files of `Travis` and `AppVeyor` have been removed.

(MODULES-10800) Add GitHub Actions workflows

This commit adds the `commits` rake task and runs it in the Static Code
Analysis workflow as a step.

Unit tests seem to be running much faster on Windows 2016 with GitHub
Actions than Windows 2019.

During the removal of `puppet-module-dev`, the pdk and puppet-blacksmith
gems were also removed by mistake. This commit makes us able to release
again.

This commit adds a job to the `[Daily] Unit Tests with nightly Puppet
gem` workflow that notifies us the conclusion of it via Slack.

…fication-job

(MODULES-10815) Add Slack notification job

Due to unknown environment changes in GitHub Actions runners, we
encountered the following error:
`fatal: cannot create directory: Filename too long`

This commit allows git to use long paths in our GitHub Actions
workflows.

…paths-in-gh-actions

(maint) Allow git to use long paths in GitHub Actions

Create a separate group in the Gemfile for pdk and puppet-blacksmith
which are only used for releasing. In the workflow, avoid installing the
release group.

Pin puppet-module-posix-system and puppet-module-win-system to an older
version since the newer ones do not bundle some gems that we use in
acceptance (i.e. beaker-module_install_helper), causing tests to fail.

Update the workflow that tests with released Puppet gems to also test
with Puppet 7.

Remove testing with Puppet 5 from the workflows since it reached EOL.

Bump Ruby version in the static code analysis workflow to 2.6, as 2.5
will be EOL soon.

(MODULES-10945) Core module spring cleaning 2021

To avoid having to update this everytime we release a new agent
platform, it should be enough to specify the supported OS, without
specific versions. It is assumed that for each OS in metadata.json, the
versions supported are the same as what the agent itself supports.

metadata

(MODULES-11167)(MODULES-11191) Add RockyLinux && AlmaLinux to host-core metadata

(MODULES-11197) Update puppetlabs-host_core to the latest pdk template

Release prep v1.1.0