onclite: fstab: Switch to FBE as default encryption method

* Switching to a different encryption method as FBE, which has no
  support to encrypt existing files, requires users to format /data completely.
  However, we are able to retain FDE functionality on already encrypted
  devices by setting encryptable=footer fstab entry.

* This commit switches the default encryption to FBE on non-encrypted devices.

* FDE support should be completely dropped in the next version of Android.

Change-Id: Id7528f11e18284dae39b7844d23129973683477e