Add ADR for command-line option handling best practices

Add comprehensive documentation for command-line option handling
best practices based on GitHub issue #1521. Includes philosophy,
architecture, and step-by-step developer guide.

Author: tautschnig

doc/ADR/README.md

@@ -6,6 +6,10 @@ where taken at the time they were, so that future maintainers
 can more easily identify constraints that shaped the architecture
 of the system and the surrounding infrastructure.
 
+## Command-Line Interface
+
+* \subpage command-line-option-handling
+
 ## Symex ready goto form
 \subpage symex-ready-goto