ceph-volume: avoid unnecessary subprocess calls

ceph-volume: avoid unnecessary subprocess calls

These calls are slowing down `ceph-volume inventory`.
Especially because of the class `ceph_volume.util.device.Devices`.
It calls the class `ceph_volume.util.device.Device` for each device found
on the host which calls many times the binaries `lsblk`, `pvs`, `vgs`, `lvs` itself.
We can make only one call in `Devices()` to gather all details and use them during the whole runtime

current implementation:

```
        1    0.000    0.000    0.892    0.892 device.py:35(__init__) (class Devices)
        8    0.001    0.000    0.853    0.107 device.py:151(_parse)
       56    0.002    0.000    0.882    0.016 process.py:154(call)
        8    0.001    0.000    0.245    0.031 lvm.py:1099(get_lvs)
        8    0.000    0.000    0.026    0.003 disk.py:231(lsblk)
        8    0.000    0.000    0.435    0.054 device.py:278(_set_lvm_membership)
        1    0.000    0.000    0.885    0.885 device.py:38(<listcomp>) (multiple calls to Device() class)
      8/5    0.000    0.000    0.885    0.177 device.py:92(__init__) (class Device)

>>> timeit.timeit('Inventory([]).main()', setup='from ceph_volume.inventory import Inventory', number=1)

Device Path               Size         rotates available Model name
/dev/sdb                  200.00 GB    True    True      QEMU HARDDISK
/dev/sda                  200.00 GB    True    False     QEMU HARDDISK
/dev/sdc                  200.00 GB    True    False     QEMU HARDDISK
/dev/sdd                  200.00 GB    True    False     QEMU HARDDISK
/dev/vda                  11.00 GB     True    False
0.9309048530412838
>>>
```

new approach:

```
        1    0.000    0.000    0.253    0.253 device.py:35(__init__) (class Devices)
        5    0.000    0.000    0.144    0.029 device.py:167(_parse)
       21    0.001    0.000    0.246    0.012 process.py:154(call)
        1    0.000    0.000    0.032    0.032 lvm.py:1110(get_lvs)
        1    0.000    0.000    0.005    0.005 disk.py:236(lsblk_all)
        5    0.000    0.000    0.062    0.012 device.py:309(_set_lvm_membership)
        1    0.000    0.000    0.179    0.179 device.py:41(<listcomp>) (multiple calls to Device() class)
        5    0.000    0.000    0.179    0.036 device.py:99(__init__) (class Device)

>>> timeit.timeit('Inventory([]).main()', setup='from ceph_volume.inventory import Inventory', number=1)

Device Path               Size         rotates available Model name
/dev/sdb                  200.00 GB    True    True      QEMU HARDDISK
/dev/sda                  200.00 GB    True    False     QEMU HARDDISK
/dev/sdc                  200.00 GB    True    False     QEMU HARDDISK
/dev/sdd                  200.00 GB    True    False     QEMU HARDDISK
/dev/vda                  11.00 GB     True    False
0.2486933789914474
>>>
```

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit bea9f4b643ce32268ad79c0fc257b25ff2f8333c)