Adding interesting focuse page for top navigation bar

[guyluz11]

Adding this effect will add a feeling of investment and pleasantness in the eye, and will help our site to stand out.

https://pub.dev/packages/cool_nav

Adding this will be tricky as our menu is on the top and this menu is for bottom navigation.
And another hard part that our top navigation bar does not take all the top row of the screen, only the right side (the top navigation bar on the left side doesn't need to implement this effect).

Our current top navigation bar

[guyluz11]

masterashu/flutter_cool_nav#1

[guyluz11]

I have fixed the error in my fork https://github.com/guyluz11/flutter_cool_nav so we can implement it.