Better preview experience for attached spreadsheets

Spreadsheets attached to Jira issues can be previewed from the issue view, however, the quality of these previews does not match the expectations. 

Currently, spreadsheets attached

• do not show the grid view, unless borders are added on the sheet around the data entered
• Portrait view only, which often pushes columns to the next page
• Multi-sheet attachments show as multipage 

The behaviour above is the same for Google spreadsheet, MS Excel files.

Customers reported that the current preview is not usable as is, they need to download each attachment to make sense of it.