Enrich block device metrics with lvm metadata

[samuelvl]

We need to know the lvm configuration it order to build the topology from the block device metrics. This information can be retrieved from the udev database to avoid mounting host devices which need the agent to run as privileged.

For example, given the following metrics:

nvme1n1p1           20.0G type=part holders=[] lvm_info=map[]
nvme1n1p127          1.0M type=part holders=[] lvm_info=map[]
nvme1n1p128         10.0M type=part holders=[] lvm_info=map[]
nvme2n1              5.0G type=disk holders=[dm-0] lvm_info=map[]
dm-0                10.0G type=lvm  holders=[] lvm_info=map[lv_name:k8s-lv dm_name:k8s--vg-k8s--lv vg_name:k8s-vg]
nvme0n1              5.0G type=disk holders=[dm-0] tags=map[]
nvme1n1             20.0G type=disk holders=[] tags=map[]

We can reconstruct the following topology:

NAME                         MAJ:MIN RM   SIZE  RO TYPE
nvme0n1                      0    5.0G   0 disk
└─k8s--vg-k8s--lv            253:0   0    10.0G  0 lvm 

nvme1n1                      0  20.0G  0 disk
├─nvme1n1p1                  0  20.0G  0 part
├─nvme1n1p127                0   1.0M  0 part
└─nvme1n1p128                0  10.0M  0 part

nvme2n1                      0    5.0G   0 disk
└─k8s--vg-k8s--lv            253:0       0  10.0G  0 lvm