Support downloading a given link

Jira issue: WP-605
Support remote move/copy using links/downloading

Jira issue: WP-605
Some TODOs
Refactor some TODOs
Change superclass constructor invocation
Use temporary directory for downloads
Use two services, test remote move/copy
Merge pull request #4 from felixjendrusch/wp-605-remote-move-copy

Support inter file system entry moving and copying