implements function to check for loaded kernel modules & try auto-load

[steiler]

implements #1360

[steiler]

now auto loading the required modules, which is ip_tables and ip6_tables for now.

[steiler]

also resolves #1329

[codecov]

Codecov Report

Merging #1363 (23967f0) into main (a3f9ad3) will decrease coverage by 0.05%.
The diff coverage is 19.04%.

@@            Coverage Diff             @@
##             main    #1363      +/-   ##
==========================================
- Coverage   20.86%   20.81%   -0.05%     
==========================================
  Files          57       58       +1     
  Lines        6275     6328      +53     
==========================================
+ Hits         1309     1317       +8     
- Misses       4845     4889      +44     
- Partials      121      122       +1     

Impacted Files	Coverage Δ
clab/config.go	47.11% <0.00%> (-2.89%)	⬇️
cmd/deploy.go	6.89% <0.00%> (-0.10%)	⬇️
utils/kernel_module.go	72.72% <72.72%> (ø)

... and 2 files with indirect coverage changes

[hellt]

Thanks @steiler!