Current Kubespray supports the Kubernetes version 1.21 or upper with
`kube_version_min_required: v1.21.0`

Then kube_version v1.20- related code is not used at all.
This deletes those code for cleanup.

feat: add variables to manage makeIPTablesUtilChains and streamingConnectionIdleTimeout kubelet parameters (#8796)

Signed-off-by: Cyril Corbon <corboncyril@gmail.com>

* Alpha-NodeSwap: allow nodes to use swap

* CI: Add Fedora 35 with experimental swap job

to remove deprecation warning:

> Flag --feature-gates has been deprecated, This parameter should be set via the config file specified by the Kubelet's --config flag.

* Enable Graceful Node Shutdown for Kubernetes >= 1.21.0

* Add sample graceful shutdown parameters

* rename ansible groups to use _ instead of -

k8s-cluster -> k8s_cluster
k8s-node -> k8s_node
calico-rr -> calico_rr
no-floating -> no_floating

Note: kube-node,k8s-cluster groups in upgrade CI
      need clean-up after v2.16 is tagged

* ensure old groups are mapped to the new ones

* Allow the eventRecordQPS setting to be set.

The eventRecordQPS parameter controls rate limiting for event recording. When zero, unlimited events can cause denial-of-service situations. For my situation, I don't need more than a setting of "5". This change allows me to configure the setting before creating the cluster.

* Allow the eventRecordQPS setting to be set.

The default settings (see types.go) is five. So, this change does not affect the cluster provisioning. However, it does allow for the setting to be changed.

* Fix reserved memory unit in kubelet configuration

Signed-off-by: Wang Zhen <lazybetrayer@gmail.com>

* Move systemReserved default values from template

Signed-off-by: Wang Zhen <lazybetrayer@gmail.com>

* Rotate kubelet server certificate.

* CI test kubelet server cert rotation

* Approve kubelet serving certificates in tests.

* Introduce kubelet_config_extra_args and kubelet_node_config_extra_args to pass params to kubelet via YAML config

* kubelet_config_extra_args is not the alternative

Change-Id: I1634ba2d2d3337243ffcdea86750003a559f2576

Signed-off-by: Robin Elfrink <robin.elfrink@eu.equinix.com>

* Add kubelet config

* Change kubelet_authorization_mode_webhook to true

* Fix lint

* Sync env file

* Refactor the kubernetes node folder

* Remove deprecated flag and fix lint