Up to 100,000 protestors are expected to descend on Essen on Saturday as the far-right Alternative for Germany (AfD) holds a two-day congress to elect its new executive, police in the western Germany city predicted. The authorities raised concerns that, while most of the expected demonstrations would be peaceful, around 1,000 leftist extremists would use violent means to disrupt the congress. Around 600 AfD delegates are meeting in the city’s Grugahalle indoor arena, with current co-leaders Alice Weidel and Tino Chrupalla seeking re-election ahead of German parliamentary elections in the autum…