add reset subcommand.

[zyjhtangtang]

/kind feature

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:
/kind bug
/kind documentation
/kind enhancement
/kind good-first-issue
/kind feature
/kind question
/kind design
/sig ai
/sig iot
/sig network
/sig storage
/sig storage

What this PR does / why we need it:

add subcommand reset to yurtctl, reference proposal https://github.com/openyurtio/openyurt/blob/master/docs/proposals/20210607-adding-subcommands-server-join-reset-for-yurtctl.md

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

other Note

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In response to this:

/kind feature

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:
/kind bug
/kind documentation
/kind enhancement
/kind good-first-issue
/kind feature
/kind question
/kind design
/sig ai
/sig iot
/sig network
/sig storage
/sig storage

What this PR does / why we need it:

add subcommand reset to yurtctl, reference proposal https://github.com/openyurtio/openyurt/blob/master/docs/proposals/20210607-adding-subcommands-server-join-reset-for-yurtctl.md

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

other Note

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[rambohe-ch]

@zyjhtangtang please fix golangci-lint error and failed unit testcases.

[Peeknut]

/lgtm except for golangci-lint error

[rambohe-ch]

/lgtm
/approve

[openyurt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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