nova lacks cpu_arch field in instance_types

Nova should have support for cpu architectures, accelerator architectures, and network interfaces as part of the definition of an instance type (or flavor using RackSpace API parlance).

Currently AWS supports two different CPU architecture types, "i386" and "x86_64". In addition, AWS describes many other instance type attributes by reference, such as: I/O Performance: (Moderate/High/Very High 10Gigabit Ethernet), extended CPU information (Intel Xeon X5570, quad-core “Nehalem” architecture), and now GPU accelerators (2 x NVIDIA Tesla “Fermi” M2050 GPUs). In order to implement similar functionality in nova, we need to capture this in a way that is accessible to advanced schedulers.