[nrfconnect] Implemented WiFiNetworkDiagnostics events generation #1312

Job	Run time
Build framework (macos-release, -sdk macosx -configuration Release)	12m 15s
Build framework (ios-release, -sdk iphoneos -configuration Release)	7m 35s
Build framework (tvos-debug, -sdk appletvos -configuration Debug)	7m 35s
Build framework (watchos-debug, -sdk watchos -configuration Debug)	10m 57s
Run framework tests (asan, -enableAddressSanitizer YES -enableUndefinedBehaviorSanitizer YES)	23m 8s
Build TV Casting Bridge example	9m 54s
Run framework tests (asan-global-storage, -enableAddressSanitizer YES -enableUndefinedBehaviorSan...	18m 9s
Run framework tests (tsan, -enableThreadSanitizer YES)	18m 44s
	1h 48m 17s

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