transform: luaxform transform script

[jlucovsky]

Continuation of #11989

Add the luaxform transform that uses a Lua script to receive and transform a sticky buffer.

Lua transforms receive arguments

• (always): length of input buffer and input buffer
• (always): number of additional arguments (may be 0)
• (when present): argument array (bounded by argument count)

Arguments are passed to the Lua script as they appear in the rule:

 luaxform:./lua/lua-transform.lua, bytes 4, offset 13, hash sha256;

When the transform is invoked, 3 additional arguments are passed (arg count will be 3)

• bytes 4
• offset 13
• hash sha256

The Lua script is responsible for parsing and using the arguments and returning a tuple: output-buffer, output-buffer-byte-count

I used this Lua script:

function init (args)
  -- Optional, no return value
end

function transform(input_len, input, argc, args)
    SCLogNotice("Input length: " .. input_len .. " arg-count: " .. argc)
    for i = 1, argc do
        print("Argument " .. i .. ":", args[i])
    end
    return string.upper(input), input_len
end

return 0

Example rule using the Lua script:

alert http any any -> any any (msg:"Lua Xform example"; flow:established;  file.data; luaxform:./lua/lua-transform.lua; content: "abc"; sid: 1;)

Link to ticket: https://redmine.openinfosecfoundation.org/issues/2290

Describe changes:

• Luaxform transform changes

Updates

• Documentation tweaks

Provide values to any of the below to override the defaults.

• To use an LibHTP, Suricata-Verify or Suricata-Update pull request,
  link to the pull request in the respective _BRANCH variable.
• Leave unused overrides blank or remove.

SV_REPO=
SV_BRANCH=OISF/suricata-verify#2090
SU_REPO=
SU_BRANCH=
LIBHTP_REPO=
LIBHTP_BRANCH=

[codecov]

Codecov Report

Attention: Patch coverage is 86.78815% with 58 lines in your changes missing coverage. Please review.

Project coverage is 83.33%. Comparing base (3a7eef8) to head (46ab626).
Report is 33 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #12072      +/-   ##
==========================================
- Coverage   83.42%   83.33%   -0.10%     
==========================================
  Files         910      913       +3     
  Lines      257642   257855     +213     
==========================================
- Hits       214949   214878      -71     
- Misses      42693    42977     +284     

Flag	Coverage Δ
fuzzcorpus	61.47% <46.76%> (-0.18%)	⬇️
livemode	19.41% <12.94%> (+<0.01%)	⬆️
pcap	44.43% <30.45%> (-0.06%)	⬇️
suricata-verify	62.67% <83.93%> (-0.09%)	⬇️
unittests	59.34% <28.47%> (-0.03%)	⬇️

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[suricata-qa]

ERROR:

ERROR: QA failed on SURI_TLPR1_alerts_cmp.

Pipeline 23227

[jlucovsky]

Continued in #12098