decode/vlan: Extend VLAN encapsulation support to 3 levels

[jlucovsky]

Continuation of #7785

This PR extends Suricata's support for VLANs from 2 to 3 levels. There is no standard for 3 levels of VLANs but 3 levels are not uncommon in some environments.

Link to redmine ticket: 2816

Describe changes:

• Increase VLAN level support to 3 levels
• List all VLAN levels in output.
• Add "Q-in-Q-in-Q" unittest.

Updates

• Update zero-initializer to address Centos-7 failure.

suricata-verify-pr: 902 #suricata-verify-repo: #suricata-verify-branch: #suricata-update-pr: #suricata-update-repo: #suricata-update-branch: #libhtp-pr: #libhtp-repo: #libhtp-branch:

[codecov[bot]]

Codecov Report

Merging #7786 (81fb232) into master (50f8779) will decrease coverage by 0.07%. The diff coverage is 88.88%.

@@            Coverage Diff             @@
##           master    #7786      +/-   ##
==========================================
- Coverage   76.08%   76.00%   -0.08%     
==========================================
  Files         662      662              
  Lines      185776   185789      +13     
==========================================
- Hits       141350   141214     -136     
- Misses      44426    44575     +149     

Flag	Coverage Δ
fuzzcorpus	60.88% <83.63%> (-0.14%)	:arrow_down:
suricata-verify	52.49% <76.92%> (-0.05%)	:arrow_down:
unittests	60.72% <56.52%> (+<0.01%)	:arrow_up:

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[jlucovsky]

Continued in #7951