Admin shows upto 500 entries fixes (#3518)

[ashutoshc8101]

Fixes #3518

Changes:

• Admin shows now upto 500 entries, available options 25, 50, 100, 200, 500

What I did?

• I modified Material Table props to add 25, 50, 100 , 200, 500 entries option
• I imported Material Icons to fix icons not showing issue in the table's pagination

Demo Link: https://pr-3624-fossasia-susi-web-chat.surge.sh

Screenshots of the change:

I have used dummy data for the screenshots.

• Users Page
• Skills Page
• Bots Page

[ashutoshc8101]

@Dilshaad21 @akshatnitd @mariobehling Please review.