Broadcast API adjustment

* Enforce raw bytes vs. structured value consistency in metadata classes
* Enforce required parameters in builder
* Rename getMaximumNumberOfBroadcast to getMaximumNumberOfBroadcasts
* Added utility method to parse and serialize LTV array

Fixes: 218683032
Bug: 218683032
Test: atest BluetoothInstrumentationTests, cts tests
Tag: #feature
Change-Id: Ia10f414bdc958b75e94276d3f645687f8b9635f9