Update net.wooga.plugins to version 3.x [ATLAS-719]

[Larusso]

Description

This update will bring the plugin net.wooga.plugins to version 3.x. With this change the groupname of the gradle plugin will change during publish so I thought it might be a good idea to change the project name as well so the groupname won't include the atlas name.

The old groupname gradle.plugin.net.wooga.gradle:atlas-github would become net.wooga.gradle:github.

This patch also includes all changes needed for the new plugin metadata description.

Changes

• net.wooga.plugins to version 3.x range
• project name and remove atlas term
• plugin publish metadata

[Azurelol]

I'm in favour of net.wooga.gradle for the group name. I don't think adding the plugin suffix is necessary unless its to disambiguate.