Re-introduce man pages to docker images

[sarahchen6]

Without the man pages, we get the following failure in dd-trace-java for the :dd-smoke-tests:java9-modules:test task:

Error: SHA-512 sum check failed!
java.lang.AssertionError: SHA-512 sum check failed!
	at jdk.jlink/jdk.tools.jlink.internal.JRTArchive.shaSumMismatch(JRTArchive.java:279)
	at jdk.jlink/jdk.tools.jlink.internal.JRTArchive.lambda$addNonClassResources$0(JRTArchive.java:227)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:214)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:197)
	at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:1024)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:570)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:560)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:635)
	at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(AbstractPipeline.java:291)
	at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:652)
	at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:658)
	at java.base/java.util.stream.ReferencePipeline.toList(ReferencePipeline.java:663)
	at jdk.jlink/jdk.tools.jlink.internal.JRTArchive.addNonClassResources(JRTArchive.java:245)
	at jdk.jlink/jdk.tools.jlink.internal.JRTArchive.collectFiles(JRTArchive.java:164)
	at jdk.jlink/jdk.tools.jlink.internal.JRTArchive.entries(JRTArchive.java:129)
	at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.lambda$readAllEntries$0(ImageFileCreator.java:145)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.readAllEntries(ImageFileCreator.java:143)
	at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.create(ImageFileCreator.java:124)
	at jdk.jlink/jdk.tools.jlink.internal.JlinkTask$ImageHelper.retrieve(JlinkTask.java:1036)
	at jdk.jlink/jdk.tools.jlink.internal.ImagePluginStack.operate(ImagePluginStack.java:194)
	at jdk.jlink/jdk.tools.jlink.internal.JlinkTask.createImage(JlinkTask.java:504)
	at jdk.jlink/jdk.tools.jlink.internal.JlinkTask.run(JlinkTask.java:285)
	at jdk.jlink/jdk.tools.jlink.internal.Main.run(Main.java:50)
	at jdk.jlink/jdk.tools.jlink.internal.Main.main(Main.java:34)
Caused by: java.nio.file.NoSuchFileException: /usr/lib/jvm/25/man/man1/keytool.1
	at java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:92)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
	at java.base/sun.nio.fs.UnixFileSystemProvider.newFileChannel(UnixFileSystemProvider.java:213)
	at java.base/sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:244)
	at java.base/java.nio.file.Files.newByteChannel(Files.java:357)
	at java.base/java.nio.file.Files.newByteChannel(Files.java:399)
	at java.base/java.nio.file.spi.FileSystemProvider.newInputStream(FileSystemProvider.java:371)
	at java.base/java.nio.file.Files.newInputStream(Files.java:154)
	at jdk.jlink/jdk.tools.jlink.internal.JRTArchive.shaSumMismatch(JRTArchive.java:269)
	... 24 more

It's unclear what changes were made such that the Java 25 image specifically fails, though no other version image has the "missing" file and we are using the same image as before the errors appeared. Open to other suggestions for addressing this error as well!

Compared to the size of the current latest image (i.e. ghcr.io/datadog/dd-trace-java-docker-build@sha256:ce0228e284e908c93b9b7e5ea6f1111515345519e2408e52745e3e7a8e29a501 with "Size": 6697196033), this image (i.e. ghcr.io/datadog/dd-trace-java-docker-build:135_merge-latest with "Size": 6714064987) is 1.0025x larger.

The fix was tested here: DataDog/dd-trace-java#10626