Output alert applayer v21.1

[catenacyber]

Link to redmine tickets:
https://redmine.openinfosecfoundation.org/issues/3827
Preliminary work for https://redmine.openinfosecfoundation.org/issues/5053

Describe changes:

• output: unify boilerplate code (trying to become a lines-of-code neutral contributor to Suricata ;-) and rising the percentage of rust files )
• output/dns: do not add empty app-layer metadata
• dnp3: restrict function scope to one file

#10300 with keeping the logging direction for each app-layer protocol

does not need SV PR

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (244a35d) 73.31% compared to head (016766b) 82.36%.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #10319       +/-   ##
===========================================
+ Coverage   73.31%   82.36%    +9.04%     
===========================================
  Files         895      966       +71     
  Lines      148215   271643   +123428     
===========================================
+ Hits       108666   223730   +115064     
- Misses      39549    47913     +8364     

Flag	Coverage Δ
fuzzcorpus	63.73% <80.15%> (+0.24%)	⬆️
suricata-verify	61.46% <98.47%> (-0.07%)	⬇️
unittests	62.92% <36.64%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

[suricata-qa]

ERROR:

ERROR: QA failed on SURI_TLPR1_alerts_cmp.

Pipeline 18159

[ct0br0]

We've been reworking things but I'm assuming the QA job is accurate. Will check tomorrow.

[catenacyber]

There is supposedly no changes to detection here.
How can I reproduce QA deviation ? Or trigger a rerun ?

[catenacyber]

Replaced by #10370