Synthesis, Structure, and Characterization of 4,4′-(Anthracene-9,10-diylbis(ethyne-2,1-diyl))bis(1-methyl-1-pyridinium) Bismuth Iodide (C<sub>30</sub>H<sub>22</sub>N<sub>2</sub>)<sub>3</sub>Bi<sub>4</sub>I<sub>18</sub>, an Air, Water, and Thermally Stable 0D Hybrid Perovskite with High Photoluminescence Efficiency