Move APIs and cloud provider types into standalone Go module in ./sdk

[xrstf]

What this PR does / why we need it:
To make it easier to use the machine-controller's types and APIs, this PR moves the Kube APIs, cloud provider types, providerconfig and userdata into a new Go module in the sdk directory. Consumers can then simply import k8c.io/machine-controller/sdk and avoid having to also import heavy cloud provider dependencies.

No changes were made to the actual API definitions.

What type of PR is this?
/kind api-change

Does this PR introduce a user-facing change? Then add your Release Note here:

Introduce a new `k8c.io/machine-controller/sdk` Go module that contains the Kube APIs, cloud provider types, providerconfig etc.

Documentation:

NONE

[xrstf]

/test all

[kubermatic-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[kubermatic-bot]

@xrstf: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-machine-controller-e2e-vmware-cloud-director	c3004f2	link	false	/test pull-machine-controller-e2e-vmware-cloud-director

Full PR test history

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.

[xmudrii]

Why do we run golangci-lint two times? Can you leave a comment in the Makefile why do we do this if this is intentional?

[xmudrii]

Looks fantastic!
/lgtm
/approve

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 76c519bdbb56d7320e8539c59219a4e2d9b54219

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: xmudrii

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [xmudrii]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[soer3n]

/cherrypick release/v1.61

[kubermatic-bot]

@soer3n: #1900 failed to apply on top of branch "release/v1.61":

Applying: it compiles
Using index info to reconstruct a base tree...
M	pkg/cloudprovider/provider.go
A	pkg/cloudprovider/provider/external/provider.go
M	pkg/controller/machine/controller.go
M	pkg/providerconfig/types/types.go
M	test/e2e/provisioning/helper.go
Falling back to patching base and 3-way merge...
Auto-merging test/e2e/provisioning/helper.go
Auto-merging sdk/providerconfig/types.go
Auto-merging pkg/controller/machine/controller.go
Removing pkg/cloudprovider/provider/vultr/types/types.go
Removing pkg/cloudprovider/provider/vsphere/types/types.go
Removing pkg/cloudprovider/provider/openstack/types/types.go
Removing pkg/cloudprovider/provider/opennebula/types/types.go
Removing pkg/cloudprovider/provider/kubevirt/types/types.go
Removing pkg/cloudprovider/provider/hetzner/types/types.go
Removing pkg/cloudprovider/provider/gce/types/types.go
CONFLICT (modify/delete): pkg/cloudprovider/provider/external/provider.go deleted in HEAD and modified in it compiles. Version it compiles of pkg/cloudprovider/provider/external/provider.go left in tree.
Removing pkg/cloudprovider/provider/digitalocean/types/types.go
Removing pkg/cloudprovider/provider/azure/types/types.go
Removing pkg/cloudprovider/provider/aws/types/types.go
Removing pkg/cloudprovider/provider/anexia/types/errors.go
Removing pkg/cloudprovider/provider/alibaba/types/types.go
Auto-merging pkg/cloudprovider/provider.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0001 it compiles

In response to this:

/cherrypick release/v1.61

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.