Implement access point discovery operations for Linux using netlink

[abeltrano]

Type

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

Side Effects

• Breaking change
• Non-functional change

Goals

• Allow automatic detection of wi-fi interfaces to be used in the API.

Technical Details

• Add libnl as dependencies (core, genl, route and modules plus debug package) with cmake targets and availability in Docker development container.
• Ensure all Linux CMake presets use the Ninja Multi-Config generator and set default configure and build presets to use the Debug configuration.
• Add generic scope-exit RAII helper to notstd library.
• Add libnl helper library libnl-helpers to aid in netlink resource management for struct nl_socket and struct nl_msg.
• Add test/utility program apmonitor on Linux to monitor access point presence changes.
• Add IAccessPointDiscoveryAgentOperations implementation AccessPointDiscoveryAgentOperationsNetlink for discovering and monitoring access point presence on Linux using netlink.
• Add unit tests for AccessPointManager and AccessPointDiscoveryAgentOperationsNetlink on Linux.

Test Results

• All unit tests pass.

Reviewer Focus

• None

Future Work

• The current implementation using netlink to monitor access point presence does not filter the interfaces for interface type (eg. wifi or not) nor their wifi interface type (eg. station vs ap). The netlink network 'link' group does not provide enough information to differentiate, so a solution using the nl80211 genl netlink interface might be used instead in a future PR as part of implementing Do not present non wi-fi interfaces and non-AP operational mode wi-fi interfaces from AccessPointManager #84.

Checklist

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