Remove IOL MAC generation

[kaelemc]

IOL generates it's own hardware MAC addresses for its interfaces. It turns out we can use these instead of generating our own MAC addresses.

This PR removes:

• The MAC address generation in containerlab.
• references in the template config to any generated MACs.
• Any other variables/structs vars which store the generated MAC addresses.

[kaelemc]

Tested this and it works, we can wait for @DanPartelly to test as well.

[DanPartelly]

Tested it as well. Working as intended.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.16%. Comparing base (9e96472) to head (aae93ee).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2262      +/-   ##
==========================================
- Coverage   51.18%   51.16%   -0.03%     
==========================================
  Files         172      172              
  Lines       16689    16682       -7     
==========================================
- Hits         8542     8535       -7     
  Misses       7235     7235              
  Partials      912      912              

Files with missing lines	Coverage Δ
nodes/iol/iol.go	82.01% <ø> (-0.65%)	⬇️