Movie: Cache the results for a week.

Cache movies results for 1 week. I initially set it to one month, but I feel that that's too long--especially if people search for new movies such as "guardians of the galaxy movie". 1d is too short (that's the default), so I went with 1 week instead.

Here's an example query: https://duckduckgo.com/?q=alien+movie
hehe at this point we might as well change that to DDG. The code is 100% different now :)