Complete and cleanup CBMC help output

[tautschnig]

Add missing options and put options in suitable option groups.

• Each commit message has a non-empty body, explaining why the change was made.
• n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Merging #6928 (1997cec) into develop (06350a0) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #6928   +/-   ##
========================================
  Coverage    77.79%   77.79%           
========================================
  Files         1568     1568           
  Lines       180317   180316    -1     
========================================
  Hits        140285   140285           
+ Misses       40032    40031    -1     

Impacted Files	Coverage Δ
src/cbmc/cbmc_parse_options.cpp	80.10% <ø> (ø)
src/goto-analyzer/goto_analyzer_parse_options.cpp	72.27% <0.00%> (ø)
jbmc/src/janalyzer/janalyzer_parse_options.cpp	48.74% <0.00%> (+0.15%)	⬆️

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[martin-cs]

Thanks!