feat: add NodePool.Spec.Type to NodePool labels

[donychen1134]

What type of PR is this?

/kind feature

What this PR does / why we need it:

The type of NodePool is not a label. So it cannot be selected easily. When NodePool being created, we can mutate it to add a label which is same as the NodePool.Spec.Type. Then different type of NodePool could be selected by k8s label selector.

Which issue(s) this PR fixes:

Fixes #125

Special notes for your reviewer:

@rambohe-ch @kadisi

Does this PR introduce a user-facing change?

The NodePool.Spec.Type will be added to NodePool.Labels and user can select different NodePool easily.

other Note

[openyurt-bot]

@donychen1134: GitHub didn't allow me to assign the following users: your_reviewer.

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In response to [this](https://github.com/openyurtio/yurt-app-manager/pull/126): > > > >#### What type of PR is this? >/kind feature > > >#### What this PR does / why we need it: >The type of NodePool is not a label. So it cannot be selected easily. >When NodePool being created, we can mutate it to add a label which is same as the NodePool.Spec.Type. >Then different type of NodePool could be selected by k8s label selector. > >#### Which issue(s) this PR fixes: > >Fixes #125 > >#### Special notes for your reviewer: > >@rambohe-ch @kadisi > >#### Does this PR introduce a user-facing change? > >```release-note >The NodePool.Spec.Type will be added to NodePool.Labels and user can select different NodePool easily. >``` > >#### other Note > > Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[openyurt-bot]

Welcome @donychen1134! It looks like this is your first PR to openyurtio/yurt-app-manager 🎉

[codecov[bot]]

Codecov Report

Merging #126 (c9da758) into master (1c77dce) will increase coverage by 0.07%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #126      +/-   ##
==========================================
+ Coverage   38.27%   38.35%   +0.07%     
==========================================
  Files          42       42              
  Lines        4776     4782       +6     
==========================================
+ Hits         1828     1834       +6     
  Misses       2704     2704              
  Partials      244      244              

Flag	Coverage Δ
unittests	38.35% <100.00%> (+0.07%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...urtappmanager/webhook/nodepool/nodepool_webhook.go	47.16% <100.00%> (+6.74%)	:arrow_up:

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[rambohe-ch]

/lgtm /approve

[openyurt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: donychen1134, rambohe-ch

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/openyurtio/yurt-app-manager/blob/master/OWNERS)~~ [rambohe-ch] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment