RFR: 8332071: Convert package.html files in `java.management.rmi` to package-info.java

[Nizar Benalla]

Please review this change. I converted the `package.html` file to `package-info.java`, because `javac` cannot recognize `package.html`.
I already brought this up [in the mailing list](https://mail.openjdk.org/pipermail/serviceability-dev/2024-May/055650.html).
The conversion was done in-place, only renaming it in git.
I also added a couple of `@since` tags, with only 2 changes I don't want to split these two fixes into separate PRs.

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Commit messages:
 - remove whitespace
 - - convert package.html to package-info.java

Changes: https://git.openjdk.org/jdk/pull/19263/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19263&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332071
  Stats: 37 lines in 2 files changed: 4 ins; 3 del; 30 mod
  Patch: https://git.openjdk.org/jdk/pull/19263.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19263/head:pull/19263

PR: https://git.openjdk.org/jdk/pull/19263