smb: New keyword smb.filename v4

[zer1t0]

Link to redmine ticket: https://redmine.openinfosecfoundation.org/issues/5082

Describe changes:

• Add new sticky buffer smb.filename to match the filenames that are being accessed by SMB through the create file request
• Add documentation for the keyword

Rule example: alert smb any any -> any any (msg: "SMB file a.txt";smb.filename; content:"a.txt";sid:1;)

suricata-verify-pr: 802

[codecov[bot]]

Codecov Report

Merging #7337 (c70c43b) into master (2ebb525) will decrease coverage by 1.90%. The diff coverage is 88.88%.

@@            Coverage Diff             @@
##           master    #7337      +/-   ##
==========================================
- Coverage   77.68%   75.78%   -1.91%     
==========================================
  Files         628      657      +29     
  Lines      185657   190093    +4436     
==========================================
- Hits       144232   144064     -168     
- Misses      41425    46029    +4604     

Flag	Coverage Δ
fuzzcorpus	60.26% <36.00%> (+2.21%)	:arrow_up:
suricata-verify	51.62% <88.88%> (-2.84%)	:arrow_down:
unittests	61.01% <36.00%> (-2.03%)	:arrow_down:

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

[jufajardini]

Added the needs rebase label due to the conflicts, sorry if I'm wrong...

[victorjulien]

Closing due to inactivity. If you're interested in picking this back up, please open a new PR addressing the comments. Thanks!