wifi: Use TLS credentials library for 802.1x certificates

[krish2718]

Is your enhancement proposal related to a problem? Please describe.
Currently, 802.1x certificates for Wi-Fi Enterprise have to be passed during build time which is okay for developement, but for production we need a runtime based solution and also for security it should trusted storage based solution.

Describe the solution you'd like

Use the existing library https://github.com/zephyrproject-rtos/zephyr/tree/main/subsys/net/lib/tls_credentials to also handle 802.1x certifications. This library provides various backends RAM, PS etc.

Describe alternatives you've considered

None.

Additional context

[jukkar]

See also #78048.

[krish2718]

Thanks. The Wi-Fi credentials still doesn't support Enterprise (certs) and might end up using TLS credentials as a backend.