Allow the display of moon phases

[cjennings]

https://wttr.in/:help` mentions the following moon phase options:

Moon phase information:

/moon                   # Moon phase (add ,+US or ,+France for these cities)
/moon@2016-10-25        # Moon phase for the date (@2016-10-25)

It would be convenient to hit 'm' on a weather forecast and display the moonphase. On that page you would have the ability to change the date for the moonphase of a different date, or quit to go back to the weather page.