Create PbapPhonebookMetadata to hold size and version information

This change introduces a metadata class to hold phonebook metadata that
typically arrives as part of the response application parameter headers.
This info contains sizing and versioning data.

Bug: 365626536
Flag: EXEMPT, mechanical refactor, no logic change + tests
Test: atest com.android.bluetooth.pbapclient
Test: m com.android.btservices
Change-Id: I85b8e732784744f76f02b579e5d5d765207430f8