userguide: add section about exception policy - v4

[jufajardini]

Link to redmine ticket: https://redmine.openinfosecfoundation.org/issues/5475 https://redmine.openinfosecfoundation.org/issues/5515

Describe changes:

• add a configuration section describing the Exception Policies
• minor typo fixes and rewordings
• incorporate what was in https://github.com/OISF/suricata/pull/7873

Updates from last PR (https://github.com/OISF/suricata/pull/7888 ):

• incorporate last PR's feedback - rewordings, typo fixes...

[codecov[bot]]

Codecov Report

Merging #7892 (c347e61) into master (a9a17c8) will increase coverage by 0.22%. The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7892      +/-   ##
==========================================
+ Coverage   75.85%   76.08%   +0.22%     
==========================================
  Files         666      666              
  Lines      186269   185998     -271     
==========================================
+ Hits       141301   141514     +213     
+ Misses      44968    44484     -484     

Flag	Coverage Δ
fuzzcorpus	60.81% <ø> (+0.32%)	:arrow_up:
suricata-verify	52.74% <ø> (+0.14%)	:arrow_up:
unittests	60.69% <ø> (+0.09%)	:arrow_up:

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

[suricata-qa]

WARNING:

field	baseline	test	%
	SURI_TLPR1_stats_chk
.app_layer.error.http.parser	1548	1103	71.25%

Pipeline 9396

[victorjulien]

Merged in #7921, thanks!