Initial pass of fetching data from gRPC backend and click to update

[kwasi]

Implementation

• Adds RPCs to fetch Input and Output executions for the target artifact
• Adds RPCs to fetch Input and Output artifacts for the input and output executions
• Pass down real Artifact and Execution objects to LineageCardRow and pass them up when an artifact is clicked.
• Partial implementation of #150 and #152

Demo

• https://screencast.googleplex.com/cast/NDgxMjQzNDIyNzMzMTA3MnwwZjVjMDM2My00MQ
• https://kubeflow-ui-07.endpoints.kwasinti-kubeflow-dev.cloud.goog/_/metadata/#/artifact_types/kubeflow.org/alpha/data_set/artifacts/3

Notes

• This is a pretty barebones PR providing just enough to get the RPC calls hooked up.
• All RPCs are executed serially.
• There is no empty state
• There is no spinner when loading data
• Has not been tested with a large data set with multiple executions or deep lineage history

---

This change is 

[kwasi]

/assign @avdaredevil /area metadata /area front-end /kind feature

[kwasi]

Updated https://kubeflow-ui-07.endpoints.kwasinti-kubeflow-dev.cloud.goog/ to use the latest version of this PR.

[avdaredevil]

/lgtm /approve

Kwasi this looks great, thanks!

Quick Note: instead of merging master, try rebasing next time (to not introduce remerges and extra commits into the parent tree)

[k8s-ci-robot]

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