Updates to visual design.

- Use sizes from spec.
- Show only contact name in call details header.
- Add spacing between contact icons.
- Updates a few assets.
- Add contentDescription to a number of elements.
- Use @dimen instead of ?attr for dimensions.

Bug: 4989127
Bug: 4989128
Bug: 5039572
Bug: 5038409
Change-Id: I3a59af44c77f739185feef39afd57193b5e0176a