[ticket/12730] Add Google+ profile field

I had to create a new custom profile field type since Google+ formats URLs differently for integer IDs and custom URLs. For custom URLs it adds a + before the URL which makes it hard to validate or format, created a new offshoot of type_string in order to compensate for that.
remove this one and try 
```
	/**
	* {@inheritDoc}
	*/
	public function get_service_name()
	{
		return 'profilefields.type.googleplus';
	}
```
instead