add feed scraping to media source page

[rahulbot]

We need to add feed scraping support to the media source detail page. This includes:

• a new SourceFeedInfoContainer DataCard that lives under the "Metadata" card on the media source detail page (pass it the media object from the store as a param)
• moving the "Content from over 100 RSS feeds" info from the intro summary paragraph on that page down to this new "SourceFeedInfoContainer"
• moving the "see all feeds" link from the intro summary paragraph to a standard "explore" action arrow icon on the data card
• adding a call to the new user_mc.feedsScrapeStatus method to the existing api_media_source_details call in source.py (ie. info['feed_scrape_status'] = user_mc.feedsScrapeStatus(media_id) or something)
• displaying the feed_scrape_status on the new data card (visible to only the PERMISSION_MEDIA_EDIT role)
• a "scrape feeds" button on the data card (visible to only the PERMISSION_MEDIA_EDIT role) that calls a new server endpoint that calls user_mc.feedsScrape(media_id) method. this should be disabled if the latest scrape status has a state of queued or running (ie. don't let the user run two scrapes at once). it should refresh the data card after the call succeeds so they see the new status

I'm picturing a data card that looks like this:

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Feed Info (->)

We are scraping content for this source from over 100 RSS Feeds.

Last Scraped: July 10, 2016
Last Scraping Status: Completed

SCRAPE THIS SOURCE FOR FEEDS

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What am I forgetting?

[rahulbot]

I rethought this a bit to simplify and put in a quick fix to the v1.3.0 release