[jay7x]

Short description

This PR adds processors.numa_nodes fact, that exposes NUMA nodes count.

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document and added a Signed-off-by annotation to each of my commits
• read and accepted the AI Policy document and added Generated-by or Assisted-by annotations to each of my commits created with the help of an AI agent
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)

[jay7x]

This PR is kind of RFC for now. Questions:

1. Do we really need it as a core fact or better to move to a module?

2. Do we want to expose cores bound to NUMA nodes also:

     NUMA node0 CPU(s):         0-6
     NUMA node1 CPU(s):         7-13
     NUMA node2 CPU(s):         14-20
     NUMA node3 CPU(s):         21-27
   

   If we want, then I'd go for structured sub-fact instead:

   "processors": {
     "numa": {
       "nodes": 4,
       "cores_per_node": [
         [0,1,2,3,4,5,6],
         [7,8,9,10,11,12,13],
         [14,15,16,17,18,19,20],
         [21,22,23,24,25,26,27]
       ]
     }
   }

   I have a real case, where that data might be useful (generating isolcpus value for kernel cmdline), but I'm not sure it's generic enough to put this into core facts again.

3. (bonus question) Do we want L[123] CPU caches structure to be exposed also? I have the same case as above, where this might be useful, but again, I'm not sure it should be a core fact.