RFR: 8358: Create release notes for JMC 9.1.0 [v2]

[Marcus Hirt]

> Release notes and images for JMC 9.1.0.

Marcus Hirt has updated the pull request incrementally with one additional commit since the last revision:

  Removing duplicate

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Changes:
  - all: https://git.openjdk.org/jmc/pull/629/files
  - new: https://git.openjdk.org/jmc/pull/629/files/51ec6272..c5687b75

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=629&range=01
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=629&range=00-01

  Stats: 11 lines in 1 file changed: 0 ins; 11 del; 0 mod
  Patch: https://git.openjdk.org/jmc/pull/629.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/629/head:pull/629

PR: https://git.openjdk.org/jmc/pull/629