fix: partition alignment on disks with 4k sectors

[smira]

Fixes #10097

See siderolabs/go-blockdevice#121

I added an option to QEMU provisioner to create disks with custom block sizes (supported for some disk types).

Unfortunately, this case can't be built as a regression as QEMU's firmware boots fine with ESP partition at 256/1024/2048 LBA.

[smira]

With --disk-blocksize=4096:

spec:
    dev_path: /dev/nvme0n1
    size: 5368709120
    pretty_size: 5.4 GB
    io_size: 4096
    sector_size: 4096
    readonly: false
    cdrom: false
    model: QEMU NVMe Ctrl
    serial: deadbeef
    wwid: nvme.1b36-6465616462656566-51454d55204e564d65204374726c-00000001
    bus_path: /pci0000:00/0000:00:0b.0/nvme
    sub_system: /sys/class/block
    transport: nvme

[smira]

With 4k sector size:

/ # fdisk -l /host/dev/vda
Note: sector size is 4096 (not 512)
Found valid GPT with protective MBR; using GPT

Disk /host/dev/vda: 12582912 sectors,     0
Logical sector size: 4096
Disk identifier (GUID): 6d5a4b04-45da-47d7-afbb-d35c9c6ae13a
Partition table holds up to 128 entries
First usable sector is 256, last usable sector is 1572858

Number  Start (sector)    End (sector)  Size Name
     1            1024           26623  100M EFI
     2           26624           26879 1024K BIOS
     3           26880          282879 1000M BOOT
     4          282880          283135 1024K META
     5          283136          308735  100M STATE
     6          308736         1572607 4937M EPHEMERAL

[smira]

/m