Change "Downloader#get" to return the File Path

[madoar]

Currently Downloader#get returns the content of the downloaded file. This behavior is not always useful, for example when the downloaded file is a binary file or an archive. Therefore I propose to change the method signature to return the location of the downloaded file and use FileUtilities separately later on if the content of the file is required.

See also https://github.com/PhoenicisOrg/scripts/pull/1048#discussion_r298833856 for more details