Steer users toward `java_export` instead of `pom_file`, etc.?

[cpovirk]

• https://github.com/bazel-contrib/rules_jvm_external?tab=readme-ov-file#publishing-to-external-repositories
• https://github.com/bazel-contrib/rules_jvm_external/blob/master/private/rules/java_export.bzl

I suspect that java_export was nonexistent or at least immature at the time that we created bazel-common. If so, we probably want people to use that instead of pom_file.

That said, the reason that I am looking at java_export today is that Protobuf thinks that it might have been involved in some trouble they had with Java 8 :) But it's not immediately clear to me whether the problem they're having is "We can't run Bazel under Java 8" (in which case they can "just" not do that) or any actual problem with targeting Java 8 (which could be more of a problem for our projects that still target Java 8).

[chaoren]

I think we can deprecate everything under bazel-common/tools in favor of the better supported official alternatives:

• jarjar_library can be replaced by jar_jar from bazel_jar_jar.
• javadoc_library can be replaced by javadoc from rules_jvm_external.
• pom_file can be replaced by java_export from rules_jvm_external.