A Study on Theoretical, Spectroscopic and Electronic Properties of New 3-phenyl-4-ethoxy-4-(4-methoxybenzoxy)-benzylidenamino]-4,5-dihydro-1H-1,2,4-triazol-5-one by using 6-311++G(d,p) DFT (B3LYP)/B3PW91 and HF Methods