Merge `version` and `allureJavaVersion` parameters

[leonsabr]

I'm submitting a ...

• [ ] bug report
• [x] feature request
• [ ] support request => Please do not submit support request here, see note at the top of this template.

What is the current behavior?

Both parameters should be specified:

allure {
    version = '2.7.0'
    autoconfigure = true
    aspectjweaver = true
    allureJavaVersion = '2.7.0'
}

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem

What is the expected behavior?

What is the motivation / use case for changing the behavior?

Please tell us about your environment:

Allure version	2.7.0
Test framework	[email protected]
Allure adaptor	[email protected]
Generate report using	[email protected]

Other information

[vlsi]

This PR adds Gradle 5.0...7.0 with a streamlined DSL: https://github.com/allure-framework/allure-gradle/pull/61 See the new DSL at https://github.com/vlsi/allure-gradle/tree/facelift#basic-usage

Please feel free to try it and provide feedback