[jfx11u] RFR: 8263760: Update gradle to version 7.0.1

[Ambarish Rapte]

There were two minor merge conflicts in `build.gradle` and one conflict in `gradle/wrapper/gradle-wrapper.properties` while cherry picking the change. 
And it also required similar changes to be made for project fxpackager. The [first commit](https://github.com/openjdk/jfx11u/pull/49/commits/7700a6d1a7c82df8fc269f1de6f3bd5119fb3397) is the original cherry pick and [second commit](https://github.com/openjdk/jfx11u/pull/49/commits/cea09bdfc96374ce00560c13e6730ab76f8b20e9) is the additional changes for fxpackager.
Verified the build on all three platforms with gradle 7.0.1 and apache ant 1.10.5

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Commit messages:
 - corrections for project fxpackager
 - 8263760: Update gradle to version 7.0.1

Changes: https://git.openjdk.java.net/jfx11u/pull/49/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx11u&pr=49&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263760
  Stats: 148 lines in 13 files changed: 46 ins; 5 del; 97 mod
  Patch: https://git.openjdk.java.net/jfx11u/pull/49.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx11u pull/49/head:pull/49

PR: https://git.openjdk.java.net/jfx11u/pull/49