Drawer - remove ability to add a border to panel

[mcoker]

In patternfly/patternfly#2887 we removed the .pf-m-border variation. All non-inline/static drawers where the panel overlays the content should have a drop shadow. All inline/static drawer panels should have a border. Either the shadow or border can be removed with .pf-m-no-border, but there is already an issue to handle that - #3983

[tlabaj]

@mcoker. is this a breaking change? The drawer is still beta? Should this not go in master?

[mcoker]

Ah good point, I forgot drawer is beta. That works for me.

[tlabaj]

Looks like core work was done on v4. So we will do the work on v4 as well.