Move LineageView key sizes to LineageView props

[kwasi]

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

This is a followup change to #183 to make it easier to migrate LineageView to a standalone repo. I'm working under the assumption that any file named Lineage*.tsx? will be moved to the Lineage module of the shared-components repo.

Changes

• Moves px() helper function out of Css.tsx into LineageCss.ts to eliminate a non-lineage dependency.
• Make cardWidth and edgeWidth props that are passed to LineageView and propagated down to LineageCard and EdgeCanvas
• Make current key sizes (cardWidth=260px, edgeWidth=120) default parameters that can be overridden by props passed to <LineageView />. The goal is to allow <ArtifactDetails /> the page/application to drive the sizes of the shared component <LineageView /> while providing reasonable defaults.

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This change is 

[kwasi]

This has no visual changes, but the changes are deployed to: https://kubeflow-ui-07.endpoints.kwasinti-kubeflow-dev.cloud.goog/_/metadata/

[avdaredevil]

/lgtm /approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: avdaredevil

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