RFR: Add JMH Visualizer as a community project

[Thanh Le]

Add JMH Visualizer as a community project

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Commit messages:
 - Remove sbt because it's already referenced.
 - Add jmh visualizer
 - Add sbt plugin as a related project

Changes: https://git.openjdk.org/jmh/pull/91/files
 Webrev: https://webrevs.openjdk.org/?repo=jmh&pr=91&range=00
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jmh/pull/91.diff
  Fetch: git fetch https://git.openjdk.org/jmh pull/91/head:pull/91

PR: https://git.openjdk.org/jmh/pull/91