Excel file support for TabPort Extension

[Jitensid]

Currently the TabPort chrome extension has the ability to download and upload information about the tabs in JSON Format. But people who are not associated with software development may not be comfortable with JSON files. If the extension can support downloading and uploading of tabs in excel format (.xlsx) then the extension can be useful to a broader audience.

About this issue

1. Once a user selects Download Tabs button they should get an option to select in which format they want to download their tabs
2. Also when Upload Tabs button is clicked excel file upload should be supported.