Create specification file output

Specification output saving should be working when a tab-delimited or spec file originally get uploaded. Saving with an NWIS upload has not been tested due to a minor issue related to the NWIS code (Sophia's branch will resolve). Folder inputs can produce a spec file, but will also need to discuss how the associated data file should be handled in the saved spec file when folder contains multiple txt/.psf files.

Ready for merge when Sophia feels we have enough for USGS team to test.