BERLIN — An adviser to Russian President Vladimir Putin has invited politicians from the Alternative for Germany (AfD) party to an economic forum in June in an illustration of how the Kremlin is cultivating ties with Germany’s far right. At least two AfD members of the Bundestag, Germany’s lower house of parliament — lawmakers Markus Frohnmaier and Steffen Kotré — are set to attend the St. Petersburg International Economic Forum after receiving invitations, according to three party politicians