added moon location as black dot

[rdoshi99]

• added function get_moonloc which returns a SkyCoord object to retrieve the RA and DEC for the moon
• plotted the location as a black dot on the skypath plot
• the coordinates seem a little off
• still working on the phase of the moon
• in progress issue #27

[rdoshi99]

• changed moonloc function to parse the night instead
• changed moon color to gold and orange for the start-of-night star
• checked the case of 20191215 by hand, found that for the tiles near the moon, the moon separation angle is only 5 degrees