RFR [9] 8178101: Migrate the thread deprecation technote to javadoc doc-files

[Chris Hegarty]

As part of the ongoing doc cleanup effort, we should move the existing
longstanding note on "Thread Primitive Deprecation" into the JDK
repository, say under jdk/src/java.base/share/classes/java/lang/doc-files,
and update the links from the Thread javadoc.

http://cr.openjdk.java.net/~chegar/8178101/

The actual document has only been minimally modified, e.g. stylesheet
link, etc, from the current version [1].

-Chris.

[1] https://docs.oracle.com/javase/8/docs/technotes/guides/concurrency/threadPrimitiveDeprecation.html