Downloadable Stock Report has no headers

[tobyaharris]

There's a Download Stock Report button in the Stock Management tab

The file opens in Excel but the cols have no headers. There are 5 cols that contain only an integer and there is no indication of what they mean.

Could a row be inserted at the top with a word or two describing the data below? Looks like A is an identifier and H is cost, but C, F and G are guesswork.

[tobyaharris]

Given how the function creating this doesn't know what each col is, fixing this might not be trivial.

https://github.com/DigitalShoestringSolutions/InventoryManagement/blob/c900f8137fec70fe77741dc13bb8a5f819f136ac/inventory_app/views.py#L271-L292

[tobyaharris]

Fixed by #35