Re-factor WpaKeyManagement conversion helpers

[abeltrano]

Type

• Bug fix
• Feature addition
• Feature update
• Documentation
• Build Infrastructure

Side Effects

• Breaking change
• Non-functional change

Goals

• Allow validation of conversion stability for WpaKeyManagement enumeration values.

Technical Details

• Refactor existing code into new function which converts a string(_view) to a single WpaKeyManagement enumeration value.
• Use range views to split the input string for parsing into a sequence of WpaKeyManagement values.
• Add test to validate conversion to/from WpaKeyManagement and std::string_view is stable.
• Add string helper to convert an arbitrary type to a std::string_view, primarily for use in range adaptors.

Test Results

• All unit tests pass.

Reviewer Focus

• None

Future Work

• None

Checklist

• Build target all compiles cleanly.
• clang-format and clang-tidy deltas produced no new output.
• Newly added functions include doxygen-style comment block.