Dashboard Design

#236 (closed)
Created new file api_dashboard.py.
Created function to fetch top five unpaid invoice amount wise and date wise.
Created function to fetch invoice count by month wise.
Created function to fetch top five customer by pending amount and supplier by invoice count.
Created function to fetch top five most bought product and service by invoice count.
Created function to fetch delivery note count by month wise.
Created function to fetch transfer note count by month wise.

In api_report.py file created function for stock on hand report call it for top five most sold product by stock wise.
Created function to fetch five stock on hand report in descending order.