Allow import of excel/CSV to create charts

[michellealva]

right now i can only create reports through queries with some data source through a database.

[michellealva]

@nextchamp-saqib also and additional option to directly add data into insights without CSV/Excel too (like how it works in spreadsheets now, if you could give a tabular view just like sheets and ask the user to enter directly in insights instead of import)

[ankush]

generic extension of this is: to define data source interface that others can plug into.

e.g. virtual doctypes (badly done, but you get the idea)

[nextchamp-saqib]

Added CSV import

I will later attempt to make CSV data work without importing