fix: Content Store can't update some patterns. (#2740)

Both Devil May Cry HD Collection.tar and AC Unity.tar fail to download
in the Content Store because of the spaces in the file names. Apparently
curl will generate errors if the url link contains spaces. the fix is to
url encode the spaces only, a process known as 'urlify'ing the link.

The implementation uses boost regex replace to perform the substitution
when the link is added to the entry. Perhaps a better fix would be to
patch the python code that generates the Store response, but I don't
have merge permissions on that repository and all the testing I have
done indicates that the problem has been resolved.