doc/dpdk: add IPS setup docs for DPDK mode v3

[lukashino]

Make sure these boxes are signed before submitting your Pull Request -- thank you.

• [X] I have read the contributing guide lines at https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Contributing
• [X] I have signed the Open Information Security Foundation contribution agreement at https://suricata.io/about/contribution-agreement/
• [X] I have updated the user guide (in doc/userguide/) to reflect the changes made (if applicable)

Link to redmine ticket:

Follow-up of #7869

Describe changes:

• grammar fixes and Jul's comments

[codecov[bot]]

Codecov Report

Merging #7876 (2312dcf) into master (fe91506) will increase coverage by 0.07%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #7876      +/-   ##
==========================================
+ Coverage   75.99%   76.07%   +0.07%     
==========================================
  Files         665      666       +1     
  Lines      185963   185998      +35     
==========================================
+ Hits       141327   141491     +164     
+ Misses      44636    44507     -129     

Flag	Coverage Δ
fuzzcorpus	60.76% <ø> (-0.10%)	:arrow_down:
suricata-verify	52.74% <ø> (+0.23%)	:arrow_up:
unittests	60.69% <ø> (-0.01%)	:arrow_down:

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

[lukashino]

Continues in #7901