Update issue template for configreport app

https://raw.githubusercontent.com/owncloud/core/master/.github/issue_template.md has now the following entry:

Log in to the web-UI with an administrator account and click on 'admin' -> 'Generate Config Report' -> 'Download ownCloud config report' This report includes the config.php settings, the list of activated apps and other details in a well sanitized form.

Might help to add this here to the issue template as well.

Good idea. I put it into the Help -> OC-Server section.

Thank you for sharing! Might be helpful.