RFR: 8332015: Add `@since` tags to jdk.httpserver

[Nizar Benalla]

Please review this simple change, aiming to fix current uses of `@since` in the source code
-The constructor BasicAuthenticator(java.lang.String,java.nio.charset.Charset) needs an `@since 14` instead of 9.
-com.sun.net.httpserver.spi: package-info.java does not contain an `@since`.
Thanks in advance.

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Commit messages:
 - update copyright year
 - add `@since` tags

Changes: https://git.openjdk.org/jdk/pull/19168/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19168&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332015
  Stats: 5 lines in 3 files changed: 3 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/19168.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19168/head:pull/19168

PR: https://git.openjdk.org/jdk/pull/19168