Use "bzip2" instead of "bzip" in optparse's compression choices for the
convert command. This is both more accurate and matches what the
ParseCompressionTypeString function expects.

The mismatch between the two parsing functions prevented compression
using bzip2 because either ParseCompressionTypeString or optparse would
generate an error when using "bzip" or "bzip2" respectively.

Fixes https://bugs.dolphin-emu.org/issues/13427

DolphinTool: Use {fmt} library

Previously, we had WBFS and CISO which both returned an upper bound
of the size, and other formats which returned an accurate size. But
now we also have NFS, which returns a lower bound of the size. To
allow VolumeVerifier to make better informed decisions for NFS, let's
use an enum instead of a bool for the type of data size a blob has.