feat: Add leader tag to etcd monitoring

Created by: xuliwenwenwen

Signed-off-by: xuliwenwenwen liwenxu@yunify.com

What type of PR is this?

/kind feature

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #kubesphere/kubesphere#1077

Special notes for reviewers:

Does this PR introduced a user-facing change?

feat: Add leader tag to etcd monitoring

Additional documentation, usage docs, etc.: