Implement GetFlyteKitMetrics endpoint

[Yicheng-Lu-llll]

TL;DR

This is part of Flytekit Metrics Exploration.

This PR Implements GetFlyteKitMetrics endpoint(also highlighted in green):

• Download flytekit spans for a particular node from remote storage.
• Send flytekit spans to console.

Checks

/api/v1/metrics/node_executions/{id.execution_id.project}/{id.execution_id.domain}/{id.execution_id.name}/{id.node_id}

Flytekit Metrics Exploration includes:

• flytekit: https://github.com/flyteorg/flytekit/pull/1683

• flyteplugins: https://github.com/flyteorg/flyteplugins/pull/361

• flyteidl: https://github.com/flyteorg/flyteidl/pull/415

• flytepropeller: https://github.com/flyteorg/flytepropeller/pull/577

• flyteadmin: https://github.com/flyteorg/flyteadmin/pull/575

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