Migrate documentation to github pages (#1523)

Switch from having all documentation contained within the README to
publishing a jekyll static site of documentation under github pages.

This allows for configuration and installation guides to be handled
separately to make for the relevant pieces to be in smaller chunks and
therefore easier to follow for users. Additionally a table of contents
can now be included in a left navigation section that ensures it should
be possible to quickly jump from the start to any section and back
again.

Include support for publishing previews and releases under separate
directories to allow for them to exist at the same time as the other
latest version of the documents.

The navigation section also includes support for accessing any of the
other versions published so that it easier to see what configuration
options exist for a given release. These will be published automatically
when releases are added.

docs/_includes/upstream-vagrant-install.html

@@ -0,0 +1,42 @@
+* Upstream Vagrant Install<br />
+Download and execute the vagrant-libvirt-qa install script (installs latest vagrant by default):
+```shell
+curl -O https://github.com/vagrant-libvirt/vagrant-libvirt-qa/blob/main/scripts/install.bash
+chmod a+x ./install.bash
+./install.bash
+```
+* Alternatively install vagrant following [https://www.vagrantup.com/downloads](https://www.vagrantup.com/downloads):
+{% if include.distro == "debian" or include.distro == "ubuntu" -%}
+```shell
+curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo apt-key add -
+sudo apt-add-repository "deb [arch=amd64] https://apt.releases.hashicorp.com $(lsb_release -cs) main"
+sudo apt-get update && sudo apt-get install vagrant
+```
+{% elsif include.distro == "fedora" -%}
+```shell
+sudo dnf install -y dnf-plugins-core
+sudo dnf config-manager --add-repo https://rpm.releases.hashicorp.com/fedora/hashicorp.repo
+sudo dnf -y install vagrant
+```
+{% elsif include.distro == "centos" or include.distro == "rhel" -%}
+```shell
+sudo yum install -y yum-utils
+sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/RHEL/hashicorp.repo
+sudo yum -y install vagrant
+```
+{% elsif include.distro == "opensuse" %}
+  As there is no upstream repository this will not be kept up to date automatically.
+  {: .warn }
+
+  ```shell
+  version="$(
+      wget -qO - https://checkpoint-api.hashicorp.com/v1/check/vagrant 2>/dev/null | \
+          tr ',' '\n' | grep current_version | cut -d: -f2 | tr -d '"'
+  )"
+  wget --no-verbose -O vagrant.rpm \
+        https://releases.hashicorp.com/vagrant/${version}/vagrant_${version}_x86_64.rpm
+  sudo zypper install --allow-unsigned-rpm --no-confirm vagrant.rpm
+  ```
+{% else -%}
+Missing the correct distro for vagrant install in site generation
+{% endif -%}