Allow to store driver specific data on a per-vcpu basis.

Move of the virDomainDef*Vcpus* functions was necessary as
virDomainXMLOptionPtr was declared below this block and I didn't want to
split the function headers.

A simple getopt-based argument parser is added for the /usr/sbin/bhyveload
command, loosely based on its argument parser.

The boot disk is guessed by iterating over all
disks and matching their sources. If any non-default arguments are found,
def->os.bootloaderArgs is set accordingly, and the bootloader is treated as a
custom bootloader.

Custom bootloader are supported by setting the def->os.bootloader and
def->os.bootloaderArgs accordingly

grub-bhyve is also treated as a custom bootloader. Since we don't get the
device map in the native format anyways, we can't reconstruct the complete
boot order. While it is possible to check what type the grub boot disk is by
checking if the --root argument is "cd" or "hd0,msdos1", and then just use the
first disk found, implementing the grub-bhyve argument parser as-is in the
grub-bhyve source would mean adding a dependency to argp or duplicating lots
of the code of argp. Therefore it's not really worth implementing that now.
Signed-off-by: NFabian Freyer <fabian.freyer@physik.tu-berlin.de>

A simpe getopt-based argument parser is added for the /usr/sbin/bhyve command,
loosely based on its argument parser, which reads the following from the bhyve
command line string:

* vm name
* number of vcpus
* memory size
* the time offset (UTC or localtime)
* features:
  * acpi
  * ioapic: While this flag is deprecated in FreeBSD r257423, keep checking for
    it for backwards compatibiility.
* the domain UUID; if not explicitely given, one will be generated.
* lpc devices: for now only the com1 and com2 are supported. It is required for
   these to be /dev/nmdm[\d+][AB], and the slave devices are automatically
   inferred from these to be the corresponding end of the virtual null-modem
   cable: /dev/nmdm<N>A <-> /dev/nmdm<N>B
* PCI devices:
  * Disks: these are numbered in the order they are found, for virtio and ahci
    disks separately. The destination is set to sdX or vdX with X='a'+index;
    therefore only 'z'-'a' disks are supported.
    Disks are considered to be block devices if the path
    starts with /dev, otherwise they are considered to be files.
  * Networks: only tap devices are supported. Since it isn't possible to tell
    the type of the network, VIR_DOMAIN_NET_TYPE_ETHERNET is assumed, since it
    is the most generic. If no mac is specified, one will be generated.
Signed-off-by: NFabian Freyer <fabian.freyer@physik.tu-berlin.de>

First, remove escaped newlines and split up the string into an argv-list for
the bhyve and loader commands, respectively. This is done by iterating over the
string splitting it by newlines, and then re-iterating over each line,
splitting it by spaces.

Since this code reuses part of the code of qemu_parse_command.c
(in bhyveCommandLine2argv), add the appropriate copyright notices.
Signed-off-by: NFabian Freyer <fabian.freyer@physik.tu-berlin.de>