RFR: 8264010: Add Gradle dependency verification [v3]

[John Neffenger]

> This pull request adds dependency verification to the Gradle builds of JavaFX on Linux, macOS, and Windows. It is the third of three changes that close the gaps in the JavaFX build security:
> 
> * [JDK-8262236][1]: Configure Gradle checksum verification
> * [JDK-8263204][2]: Add Gradle Wrapper Validation Action
> * [JDK-8264010][3]: Add Gradle dependency verification
> 
> "Without dependency verification it's easy for an attacker to compromise your supply chain," warns the [Gradle User Guide][4]. All three changes come from conference talks by members of the Gradle team, available as [PDF slides][5] or on YouTube in the following two videos:
> 
> * [Cédric Champeau at Devoxx][6] in November 2019
> * [Louis Jacomet at Jfokus][7] in February 2020
> 
> "We all run in a crazy-unsafe environment, in a way," says Louis Jacomet at the end of his talk. These three changes make it just a little less crazy-unsafe for all of us building JavaFX, regardless of our system, network, or country.
> 
> [1]: https://bugs.openjdk.java.net/browse/JDK-8262236
> [2]: https://bugs.openjdk.java.net/browse/JDK-8263204
> [3]: https://bugs.openjdk.java.net/browse/JDK-8264010
> 
> [4]: https://docs.gradle.org/current/userguide/dependency_verification.html
> [5]: https://www.jfokus.se/jfokus20-preso/Protecting-your-organization-against-attacks-via-the-build-system.pdf
> [6]: https://youtu.be/GWGNp3a3hpk
> [7]: https://youtu.be/bwiafNatsf0

John Neffenger has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Add dependencies for media and WebKit libraries
 - Merge branch 'master' into dependency-verification
 - Add a README file and update 'UPDATING-lucene.txt'
 - 8264010: Add Gradle dependency verification

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

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/437/files
  - new: https://git.openjdk.java.net/jfx/pull/437/files/c7ac7f62..7609914a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=437&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=437&range=01-02

  Stats: 87251 lines in 1199 files changed: 49762 ins; 13569 del; 23920 mod
  Patch: https://git.openjdk.java.net/jfx/pull/437.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/437/head:pull/437

PR: https://git.openjdk.java.net/jfx/pull/437