Upload and store non-XML data document(s) into an XML Library.
Documents are uploaded in POST multipart, then stored as non-XML documents.
mime-type: text/plain
For each document that could not be generated, return a line containing the error code, the destination path of the Document, and the error message separated by tabs.
The last line is of the form: IMPORT ERRORS #errors, where #errors the number of import errors. Therefore a completely successful put returns a single line 'IMPORT ERRORS 0'.