fstab: mount external storage

* Vold handles mounts in 4.4

Signed-off-by: bmc08gt <brandon.mcansh@gmail.com>
d2: Move feature dependent overlays

Signed-off-by: bmc08gt <brandon.mcansh@gmail.com>
d2: Use device specific libhealthd

* d2 has different battery capacity path than default

Signed-off-by: bmc08gt <brandon.mcansh@gmail.com>