[etcd]: add etcd distributed tracing flags

[ugur99]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This MR contains small enhancements that allows us to enable ETCD distributed tracing.
Related parameters and variables are defined.

Which issue(s) this PR fixes:

Fixes # none

Special notes for your reviewer:
Since it is strongly recommended that the experimental-distributed-tracing-instance-id be unique for each instance, I assigned it to etcd_member_name value which is unique for per etcd instance instead of giving it as a parameter.

Ref: Etcd distributed tracing documentation

Does this PR introduce a user-facing change?:

[etcd] add etcd distributed tracing flags (`etcd_experimental_enable_distributed_tracing`,`etcd_experimental_distributed_tracing_sample_rate`,`etcd_experimental_distributed_tracing_address`,`etcd_experimental_distributed_tracing_service_name`), feature is disabled by default

[k8s-ci-robot]

Hi @ugur99. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[floryut]

@ugur99 Thank you for the PR 👍
/ok-to-test

[ugur99]

hi @floryut! I saw some failed pipelines but not sure if they are related to my changes; please ping me if I need to do stg to fix it.

[ugur99]

Hi again @floryut! All jobs are successful now I guess

[mzaian]

Thanks @ugur99

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: floryut, mzaian, ugur99

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[yankay]

Thanks @ugur99
/lgtm