Implemented Buttons to Toggle between Pages

[N-Shar-ma]

Fixes #983

Changes Made:

• Added a state variable for currentPageNo
• Implemented a next page button which increments currentPageNo by 1 (disabled if currentPageNo===pageCount)
• Implemented a previous page button which decrements currentPageNo by 1 (disabled if currentPageNo===1)
• Only display the Output component if its associated pageNo=currentPageNo using a boolean show prop
• Made sure that if the user removes the last page while it is active, currentPageNo is switched to its previous page

Screenshot: