RFR: Initial implementation of RestRequest cache expiration

[Robin Westberg]

Check the age of cached pages before reusing them to avoid incorrectly receiving stale date from misbehaving caches.

Best regards,
Robin

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Commit messages:
 - Initial implementation of restrequest cache expiration

Changes: https://git.openjdk.java.net/skara/pull/845/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=845&range=00
  Stats: 24 lines in 1 file changed: 22 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/845.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/845/head:pull/845

PR: https://git.openjdk.java.net/skara/pull/845