decouple yurtctl with yurtadm

[Congrool]

Signed-off-by: Congrool chpzhangyifei@zju.edu.cn

What type of PR is this?

/kind enhancement

What this PR does / why we need it:

Decouple yurtctl with yurtadm. Before this pr, code in pkg/yurtctl imported package in pkg/yurtadm, which makes code confused for read and difficult to maintain. This pr totaly separates yurtctl from yurtadm.

The following work was done in this pr:

1. move pkg/yurtadm/kubernetes to pkg/util/kubernetes for general use
2. move pkg/yurtadm/util/templates and pkg/yurtadm/util/strings to pkg/util/templates and pkg/util/strings respectively for general use
3. move constants which are only used by yurtctl from pkg/yurtadm to pkg/yurtctl
4. move functions that only used by yurtctl from pkg/yurtadm/util/kubernetes to pkg/yurtctl/util/kubernetes

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

/assign @rambohe-ch @lonelyCZ

Does this PR introduce a user-facing change?

other Note

[rambohe-ch]

/lgtm
/approve

[openyurt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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