Add command to validate system configuration

[tatry]

The idea is to add a command like nikss-ctl validate (specific only to CLI) which validates system configuration to have ability to run eBPF programs:

• BPF filesystem mounted in the right place (should be on /sys/fs/bpf, can be checked with mount -l | grep bpf).
• Supported kernel version (at least 5.8).
• Kernel compiled with necessary options (options like CONFIG_BPF=y, see kernel configuration for BCC).
• Supported architecture (x64/amd64 were tested only).
• Maybe: available p4c-ebpf compiler and clang version >= 10.0.0 (older may not generate correct programs, this version is tested).