Uniform snaps header & footer

[eriknson]

We're facelifting our headers and footers to make them consistent cross our snaps custom UI surfaces (dialogs & home pages)

Let's make them;

• always visible / sticky
• height 64px for the headers & 74px for the footers
• background/default color
• shadow/md
• let’s drop the snaps badge & origin from the header

[eriknson]

In addition to above, let's also change the background color to background/alternative as well as adding;

• border/muted to our copyable component
• make sure all inputs / dropdowns have background/default and border/muted around them
• potentially bump our muted text states to text/alternative (reach out to me and we'll look into it)

[eriknson]