return folder as part of file metadata

[robkooper]

When returning the file information besides the name, etc, we should return the folder it is in the dataset.

[MBcode]

looking folder/file for metadata *

[MBcode]

https://github.com/MBcode/clowder/tree/return_folder_as_part_of_file_metadata has
val foldersContainingFile = folders.findByFileId(file.id)
"folders" -> foldersContainingFile.toString()
but can make prettier like in to_jsonld(), w/the display of the folder names+IDs

[MBcode]

jsonfFile additions:
val allPaths: List[List[String]] = (for (folder <- foldersContainingFile) yield (folderPath(folder, List()).tail))
"path" -> allPaths.map(xl => "/" + xl.map(x => x.toString()).mkString("/")).mkString("")
output: "path": "/folder-1/folder-2", ;just drop the trailing comma, if only 1 path?

[MBcode]

for PR369
api.Files jsonfile, adds to fields "downloads" and "views"
added to CHANGELOG.md
Will create a new issue378, to turn above toString() fields into int, along with "size" which in now also a string