Installed SonarQube version does not support Java 10 which is recommended in the instructions

[sonarqube-azuresql](https://github.com/Azure/azure-quickstart-templates/tree/master/sonarqube-azuresql#secure-sonarqube-vm-with-azure-sql-db)

### Issue Details

The version of SonarQube that ships with the template does not work with Java 10. The install instructions point explicitly to this Java version to be installed.

### Repro steps (*if necessary, delete otherwise*)
1. Deploy template on Azure.
2. Install Java 10 from the URL in the install instructions.
3. Restart the server.
4. Check the SonarQube logs at `C:/sq/sonarqube-5.6.4/logs/sonar
5. Verify SonarQube did not start with the error `Unrecognized VM option 'UseParNewGC'`.

### Solution

- Either install Java 8 (instructions should be updated) or
- change Java arguments to a collector supported by Java 10 (haven't tested, apparently not officially supported).

Start with the sonarqube-azuresql template and its linked secure SonarQube VM installation instructions. Deploy the template, install the documented Java version, restart the server, and inspect C:/sq/sonarqube-5.6.4/logs/sonar for the UseParNewGC failure; done means the instructions and configuration agree on a supported Java version and SonarQube starts successfully.

Written by the indexing model from the issue text.