Add ClusterTemplate API support

[JohnNiang]

What type of PR is this?

/kind feature

What this PR does / why we need it:

We have a few use cases:

1. Official predefined Templates
2. Some platform managers may need to create some common Templates for all departments to use.

So I create a new API: ClusterTemplate.devops.kubesphere.io, corresponding to Template.devops.kubesphere.io, for the above scenarios.

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Related to #453.

Does this PR introduce a user-facing change??

None

/label tide/merge-method-squash

[codecov]

Codecov Report

Merging #462 (703e576) into master (0c15a48) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #462      +/-   ##
==========================================
+ Coverage   76.93%   76.98%   +0.04%     
==========================================
  Files         118      118              
  Lines       22223    22218       -5     
==========================================
+ Hits        17098    17104       +6     
+ Misses       4946     4936      -10     
+ Partials      179      178       -1     

Flag	Coverage Δ
unittests	76.98% <100.00%> (+0.04%)	⬆️

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

Impacted Files	Coverage Δ
pkg/api/devops/v1alpha1/clustertemplate_types.go	100.00% <100.00%> (ø)
controllers/template/template_controller.go
...ontrollers/jenkins/pipeline/pipeline_controller.go	43.18% <0.00%> (+3.78%)	⬆️

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[LinuxSuRen]

/lgtm
/approve

[ks-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JohnNiang, LinuxSuRen

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