CentOS 8, CI testing for libvirt, MTU fixed and more

• Added CentOS 8 support
• Added CI testing for libvirt
• Fixed the "set MTU service", this is useful when the host you are running on uses a VPN (see NETWORK_VM_MTU and KUBE_NETWORK_MTU)
• Many other smaller enhancements (e.g., readme updated)

Updated Calico and Canal versions to v3.14

v1.9.0

Merge pull request #68 from galexrt/update_calico_canal

Added environment variable to install additional packages into the VMs

Added environment variable INSTALL_ADDITIONAL_PACKAGES to install additional packages into the VMs without needing to modify Vagrant code directly.

New features: Proxy vars, kube-web-view addon and reworked (env) variable usage

New features: Proxy vars, kube-web-view addon and reworked (env) variable usage added in #66.

Updated CNI manifests, install Docker from official repos and fix miscellaneous issues

• cni: update all CNIs to latest version cni: update all CNIs to latest version
• *: install docker from official docker repos *: install docker from official docker repos
• vagrantfile: fixed retry loops vagrantfile: fixed retry loops
• vagrant: remove pre variables file vagrant: remove pre variables file

Libvirt: Allow storage pool to be configured

Thanks to @lalbers for implementing this in #59!

Added libvirt support

This release adds libvirt support (at least on my machine the master VM for some reason hangs at "waiting for domain to get IP", doing a "Force Reset" on the VM fixes the issue).

Besides that new Makefile targets have been added, like ssh-config.
Checkout the make help menu for more information.

Want to connect to the VMs using your own SSH key? No problem set the USER_SSHPUBKEY to a path of a SSH public key file (can also be multiple as long as it is in one file).