Add automatic selection of lbaf value based on a single sector size. The
lbas (the data sector size) is selected based on the power of 2 in the
sector size, and the metadata size is selected by the remainder. If an
lbaf matches these values is used, otherwise we exit with an error.
When there's a tie, we prefer the higher performance.

Manual selection of these values remains as well for times when we
select incorrectly.

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