fstab: configurable zram, swapped partitions, remove duplicate recovery version

* Remove recovery.fstab
* Split fstab into regular and swapped (/system <-> /data)
* Dynamically configure the appropriate mmc device for recovery vs
  regular fstab type
* Configurable zRAM size via BOARD_ZRAM_SIZE
* Enable swapped partitions via BOARD_SWAP_SYSTEMDATA := true

Change-Id: Icfd8cf75f9242dcfb6da67e536b756e464f54767