CopySearchOptionsTask should not use group as parameter name

[crism]

Describe the bug
If a task of type CopySearchOptionsTask is put into a Gradle task group, the task tries to use the Gradle task group as part of the options URI, e.g. /Copy Options/data-hub-FINAL/rest-api/options/foo.xml.

To Reproduce
Steps to reproduce the behavior:

1. Create a task of type CopySearchOptionsTask and assign it to a group.
2. Run the task.
3. Observe the resulting error.

Expected behavior
Assigning a task to a group should not affect its behavior.

The task class uses group as an input name. Since group is meaningful to Gradle, tne task parameter should be named something else.

[rjrudin]

@crism We'll take care of this in the upcoming 6.1.0 release.