Dialpad modifications to match the rest of the redlines

* Reduced size of star and pound keys
* Made star and pound key gray
* Add voicemail image view
* Add light versions of menu assets
* Renamed other menu assets to be more consistent
* Assign proper menu items to dialpad fragment

Change-Id: I67f2e7eecb177fc8ab7b4bc9b2855b385c622a7f