Add support for using full path instead of depending on temp path

[crisberrios]

Adding a Path setting instead of forcing Temp path for file name would be a nice addition.

[ajepst]

Hmmm revisiting this code, the SheetsGetterFromFile is expecting a stream, and just uses the temp dir to get a real file from the stream. It would also be very reasonable to want to read a pre existing on-disk file, and that seems like a really important missed use case that absolutely needs to be added.

As for the original issue, I suppose someone might want to do the temporary stream conversion in a location other than temp, (security reasons, maybe?) so might be worth having the temp directory used for conversions overridable via some sort of new optional configuration.

[ajepst]

(Revisiting, further thinking) Main thing with changing the path used for file creating from streams would be changing the behavior of XlsxFileCreator. I don't think we'd want to have to pass that in, especially given that the intent is for it to be throwaway. (If you want to actually save this file, you might want to do that before processing and use a file import.) I think some sort of global configuration for this makes sense (otherwise it'd use temp) Maybe an App.config setting? Or maybe, some sort of static setting that'll go across the board for everything. I want something that'll work easily without a container, so probably not a simple constructor parameter on XlsxFileCreator since that wouldn't play well with the poor man's DI it has for non-container use.