[Frontend] reduces the size of the stylesheet

[bechir]

Our base stylesheet have many code duplication
As described here in sonarcloud and here the code may be reduced in size. And the html template does not use all the power of bootstrap.

Use the power of bootstrap bootstrap
For example the buttons have theirs stylesheets rules like padding while bootstrap have px-*, pl-*, pr-* for horizontal paddings, py-*,pt-*, pb-* , for vertical padding, we can use them perfectly.

So, help wanted, please contribute!