Remove reliance on program information website

[stscijgbot-jwql]

Issue JWQL-261 was created on JIRA by Bryan Hilbert:

Related to JWQL-260. Any time the program information site goes down, which seems to happen fairly frequenty, JWQL crashes as well because it cannot load a webpage to scrape for proposal information. 

It seems likely that the information contained on that website could also be retrieved from pyvo or a MAST query. It might be better for us to switch to that long-term, just so that we are not dependent on the slightly unstable program information page.