feat: add CustomScripts.Role property

[will4j]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Support custom scripts executing on some specfic nodes when creating a cluster, make kubekey more flexible for different scenes.

Take examples below：

apiVersion: kubekey.kubesphere.io/v1alpha2
kind: Cluster
metadata:
  name: dubhe-open-cluster
spec:
  hosts:
    - { name: master, address: 192.168.10.1, internalAddress: 192.168.10.1, user: ubuntu, password: "ubuntu" }
    - { name: storage, address: 192.168.10.2, internalAddress: 192.168.10.2, user: ubuntu, password: "ubuntu" }
  roleGroups:
    control-plane:
      -  master
    nfs-server:
      - storage
  system:
    preInstall:
      - name: install nfs server
        # new added `role` property
        role: nfs-server
        bash: /bin/bash -x install_nfs_server.sh
        materials:
          - ./scripts/install_nfs_server.sh

preInstall script 'install nfs server' will only executed at storage node.

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Does this PR introduced a user-facing change?

Add new optional property `role` for CustomScripts to let custom scripts like `PreInstall` only executed at specific nodes.

Additional documentation, usage docs, etc.:

[will4j]

/assign @pixiake

[pixiake]

@will4j Thanks for this contributions ! /lgtm /approve

[ks-ci-bot]

LGTM label has been added.

Git tree hash: e12a56a74e979d48aa686bd1426d5792ca5fe9df

[ks-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: pixiake, will4j

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