Moved the function that searches for the boot partition index to the
PartitionTable struct as a method. The method returns -1 if not found
and it's now the responsibility of the caller to handle the case where
it is not found.
Now that we have an abstract partition table definition, we can use it to
generate org.osbuild.fstab stage options.
This is extremely nice because it removes magic contains.
Signed-off-by: Ondřej Budai <ondrej@budai.cz>
Using osbuild.QEMUAssemblerOptions to encode a partition table was weird.
This commit introduces a disk package that contains data types for defining
partition tables. Also, there's a handy function to convert the abstact
partition table to osbuild.QEMUAssemblerOptions.
Signed-off-by: Ondřej Budai <ondrej@budai.cz>
