This commit removes `integTest` task from all es-plugins.
Most relevant projects have been converted to use yamlRestTest, javaRestTest,
or internalClusterTest in prior PRs.
A few projects needed to be adjusted to allow complete removal of this task
* x-pack/plugin - converted to use yamlRestTest and javaRestTest
* plugins/repository-hdfs - kept the integTest task, but use `rest-test` plugin to define the task
* qa/die-with-dignity - convert to javaRestTest
* x-pack/qa/security-example-spi-extension - convert to javaRestTest
* multiple projects - remove the integTest.enabled = false (yay!)
related: #61802
related: #60630
related: #59444
related: #59089
related: #56841
related: #59939
related: #55896
This commit does three things:
* Removes all Copyright/license headers for the build.gradle files under x-pack. (implicit Apache license)
* Removes evaluationDependsOn(xpackModule('core')) from build.gradle files under x-pack
* Removes a place holder test in favor of disabling the test task (in the async plugin)