Preserve filenames for AbstractDocuments

[isc-svelury]

When nested folder structure is not enabled, files are now mapped into folders corresponding to their extension. No further folder nesting occurs.

To enable this behavior, turn off the folder switch in the settings. Note, this only works for a universal file type mapping. So the coverage must be *

This PR also fixes the bug where some file extensions were being changed to .cls incorrectly.

Closes #92 and #93

[CraigRegester]

Not sure I quite follow the commit comment. Is this suggesting we can't folder the "Other" objects at all or that they need to be in one big folder? (E.g., .LUT files mixed with .HL7 files)

[isc-svelury]

You will be able to folder "Other" objects. There is now a toggle added to each of the defined mappings in the settings UI to switch off automatic nested folder creation from splitting up a filename by . . Once you switch off the toggle, the text box where you fill in the path should become a readonly field and have NoFolders filled in.

This means that when you export those files out, the files will be stored in a folder corresponding to their extension (hl7/ for .hl7 files and so on) and no further nesting and/or directory creation takes place. So filenames for these files will be preserved.

[CraigRegester]

Perfect, that makes sense now and what I hoped would be the case.