add a new class to have a button display like the bar

[bobzer]

Thank you for this theme !, I love your work and glad to start my journey creating a nice dashboard with it.
I'm using the kiosk_mode to remove the header and sidebar, so when I navigate I need a way to navigate back.
My sub view start with a bar and i would have a button taking space and just saying back or something.
So create a new class button-bar which combine a button and a markdown bar styling.
so here we go 😄 in order :

• without icon nor state nor entity
• with an icon
• with an icon and an entity
• with an icon, state and entity
  

hope you'll like it and will work for you too.

PS: I also did some cleaning/refactoring
also the fix a bug in the min-height for button which is was not the same everywhere (50 for lozenge and 60 for the rest) it's now 45 everywhere

[bobzer]

@th3jesta I know this can't be merged anymore because of the conflict, but I was wondering if you have interest in that ?
if no could I improve it ?
I don't want to waste time to update it for V3 if you have no interest in merging it