✨ Support RKE2ControlPlane mhc remediation

[MaxFedotov]

kind/feature

What this PR does / why we need it:

This PR adds support for RKE2ControlPlane remediation. The code is taken from KCP (https://github.com/kubernetes-sigs/cluster-api/blob/main/controlplane/kubeadm/internal/controllers/remediation.go) and adopted for RKE2. It also adds a new rcp_remediation_test e2e test, based on CAPI e2e KCPRemediationSpec.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #626

Special notes for your reviewer:

Checklist:

• squashed commits into logical changes
• includes documentation
• adds unit tests
• adds or updates e2e tests

[furkatgofurov7]

Hey, thanks for the PR 👍🏼
I have not looked into the logic yet, but can you please first rename the KCP mentions with RKE2ControlPlane everywhere (comments, file names, vars etc)?

[MaxFedotov]

Hey @furkatgofurov7, done. The only place where i left kcp is in tests, because i've used the standard capi KCPRemediationSpec test

[furkatgofurov7]

@MaxFedotov you can run make lint locally to make sure lint CI passes here

[MaxFedotov]

@furkatgofurov7, done

[MaxFedotov]

hey @furkatgofurov7! Is there anything else i can do to proceed with this PR? Thanks!

[furkatgofurov7]

This and related changes to ARCH usage in Makefile are partially reverting the change we merged moving from docker build to docker buildx. I am curious to know why this change is required since we have a list of target platforms already defined to build the images?

[MaxFedotov]

The problem here is that i'm using apple silicon to build the image, so

cluster-api-provider-rke2/Makefile

Line 120 in c75777e

ARCH ?= $(shell go env GOARCH)

will return arm64.
With the --load flag, docker daemon is trying to upload darwin\arm64 image to local docker daemon, which uses linux, which leads to the following error:

ERROR: failed to solve: rpc error: code = Unknown desc = cannot load darwin image on linux

If we don't won't to hardcode the platform, I will add additional variable

TARGET_PLATFORM = linux/$(ARCH)

and use it in docker-build-rke2-bootstrap and docker-build-rke2-control-plane:

	DOCKER_BUILDKIT=1 BUILDX_BUILDER=$(MACHINE) docker buildx build \
			--platform $(TARGET_PLATFORM) \
			--load \
			...

[MaxFedotov]

Sorry for the force push, had to rebase the branch to the latest main to fix the conflicts