Add Gradle dependency verification

Add dependency verification to the Gradle builds of JavaFX on Linux, macOS, and Windows. The verification file documents the dependencies and guarantees the integrity of the JAR and POM files downloaded during the build.

SYSTEM / OS / JAVA RUNTIME INFORMATION

Ubuntu 20.04.2 LTS
  $ uname -srm
  Linux 5.4.0-67-generic x86_64

macOS 11.2.3 (Big Sur)
  $ uname -srm
  Darwin 20.3.0 x86_64

Microsoft Windows 10 Pro Version 10.0.19042
  $ uname -srm
  CYGWIN_NT-10.0 3.1.7(0.340/5/3) x86_64

Oracle OpenJDK 15.0.2
  $ java --version
  openjdk 15.0.2 2021-01-19
  OpenJDK Runtime Environment (build 15.0.2+7-27)
  OpenJDK 64-Bit Server VM (build 15.0.2+7-27, mixed mode, sharing)

STEPS TO REPRODUCE

Reproduce the problem in two steps:

1. Modify the JAR file of a dependency in the Gradle cache:
  $ strip-nondeterminism $(find ~/.gradle -name ST4-4.1.jar)

2. Build JavaFX:
  $ bash gradlew sdk jmods

I made a non-destructive change to the 'ST4-4.1.jar' file with the Linux 'strip-nondeterminism' command, which modifies the order and modification times of the files in the archive.

EXPECTED RESULTS

  $ bash gradlew sdk jmods
  ...
  > Task :graphics:generateGrammarSource FAILED

  FAILURE: Build failed with an exception.

  * What went wrong:
  Execution failed for task ':graphics:generateGrammarSource'.
  > Dependency verification failed for configuration ':graphics:antlr'
    One artifact failed verification: ST4-4.1.jar (org.antlr:ST4:4.1)
    from repository MavenRepo
    This can indicate that a dependency has been compromised.
    Please carefully verify the checksums.
  ...
  BUILD FAILED in 1s
  5 actionable tasks: 2 executed, 3 up-to-date

ACTUAL RESULT

  $ bash gradlew sdk jmods
  ...
  BUILD SUCCESSFUL in 1m 41s
  134 actionable tasks: 134 executed

SOURCE CODE FOR AN EXECUTABLE TEST CASE

None.

WORKAROUND

None.