(Reuters) -President Vladimir Putin asserted Russia’s strength and resilience on Friday against a Western world that he accused of colonial arrogance and trying to crush his country with an economic “blitzkrieg” of sanctions. Addressing the St Petersburg International Economic Forum, a showcase event being held this year with almost no Western participation, he returned time and again to the theme of Russia’s sovereignty in a new global order: “We are strong people and can cope with any challenge. Like our ancestors, we will solve any problem, the entire thousand-year history of our country sp…