RFR: 7576: Remove the need for a local jetty server for dependencies [v2]

[Austin Brooks]

> Using newer Tycho features to achieve result:
> 
> Maven dependencies in a target (Tycho 2.2 ): https://github.com/eclipse/tycho/blob/master/RELEASE_NOTES.md#support-for-m2e-pde-maven-target-locations
> Nested target to cut down on duplicate third party code (Tycho 2.6): https://github.com/eclipse/tycho/blob/master/RELEASE_NOTES.md#support-for-nested-targets
> 
> Note: Due to change in 2.7, you must delete a file when switching branches due to changes in the `.m2` folder: https://github.com/eclipse/tycho/blob/master/RELEASE_NOTES.md#caution-when-switching-between-tycho-versions

Austin Brooks has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:

 - Update latest targets to point to third-party
 - Merge branch 'master' into removeJettyMerged
 - Remove references to third-party from scripts/
 - Fix clean target trying to access third-party directory
 - XXX: Remove needing to use a local jetty server for dependencies

-------------

Changes: https://git.openjdk.org/jmc/pull/387/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=387&range=01
  Stats: 503 lines in 9 files changed: 138 ins; 362 del; 3 mod
  Patch: https://git.openjdk.org/jmc/pull/387.diff
  Fetch: git fetch https://git.openjdk.org/jmc pull/387/head:pull/387

PR: https://git.openjdk.org/jmc/pull/387