RFR: 7831: Add new view for hierarchical edge bundling [v11]

[Brice Dutheil]

> Joint effort with @cimi to provide _hierarchical edge_ visualization to JMC.
> 
> ![Hierarchical Edge view](https://user-images.githubusercontent.com/803621/176186654-04f458f5-6f7d-4755-822c-f63e53ccfc31.png)
> 
> Here when the mouse hovers `java.util.concurrent` on the bottom right. One can see the relations with other packages.
> 
> 
> Based on the preliminary work of @cimi here : https://observablehq.com/@cimi/jfr-graph-hierarchical-edge-bundling

Brice Dutheil has updated the pull request incrementally with one additional commit since the last revision:

  Prevent NPE when switching diagrams with nothing loaded

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Changes:
  - all: https://git.openjdk.org/jmc/pull/405/files
  - new: https://git.openjdk.org/jmc/pull/405/files/43e16f09..710f4066

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=405&range=10
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=405&range=09-10

  Stats: 7 lines in 2 files changed: 5 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jmc/pull/405.diff
  Fetch: git fetch https://git.openjdk.org/jmc pull/405/head:pull/405

PR: https://git.openjdk.org/jmc/pull/405