Add cpu/ram allocation ratio to the hypervisor details

cpu_allocation_ratio and ram_allocation_ratio were useful in some circumstances. They are maybe different for each node and tough to get. So add them in hypervisor details , and can be accessable when excuate nova hpyervisor-show UUID. An example like this:
+----------------------------+------------------------------------------------+
| Property | Value |
+----------------------------+------------------------------------------------+
| cpu_allocation_ratio | 8.0 |
| cpu_info_arch | x86_64 |
| cpu_info_features | ["pge", "avx", "xsaveopt", "clflush", |
| | "sep", "syscall", "tsc-deadline", |
| | "dtes64", "msr", "xsave", "vmx", "xtpr", |
| | "cmov", "pcid", "est", "pat", "monitor", |
| | "smx", "pbe", "lm", "tsc", "nx", "fxsr", |
| | "tm", "sse4.1", "pae", "sse4.2", |
| | "pclmuldq", "acpi", "vme", "mmx", |
| | "osxsave", "cx8", "mce", "de", "rdtscp", |
| | "ht", "dca", "lahf_lm", "pdcm", "mca", |
| | "pdpe1gb", "apic", "sse", "pse", "ds", |
| | "invtsc", "pni", "tm2", "aes", "sse2", |
| | "ss", "ds_cpl", "arat", "ssse3", "fpu", |
| | "cx16", "pse36", "mtrr", "popcnt", |
| | "x2apic"] |
| cpu_info_model | SandyBridge |
| cpu_info_topology_cells | 2 |
| cpu_info_topology_cores | 8 |
| cpu_info_topology_sockets | 1 |
| cpu_info_topology_threads | 2 |
| cpu_info_vendor | Intel |
| current_workload | 8 |
| disk_available_least | 12099 |
| free_disk_gb | 15053 |
| free_ram_mb | 47089 |
| host_ip | 172.50.10.8 |
| hypervisor_hostname | node-6.domain.tld |
| hypervisor_type | QEMU |
| hypervisor_version | 2009000 |
| id | 7 |
| local_gb | 15891 |
| local_gb_used | 838 |
| memory_mb | 131046 |
| memory_mb_used | 83957 |
| ram_allocation_ratio | 1.0 |
| running_vms | 41 |
| service_disabled_reason | None |
| service_host | node-6.domain.tld |
| service_id | 43 |
| state | up |
| status | enabled |
| vcpus | 16 |
| vcpus_used | 42 |
+---------------------------+------------------------------------------+