Implement AVRCP Controller (Client) Browsing.

Following is included as part of the features:
a) Browsing for all 4 scopes (Media, VFS, Player and Now Playing)
b) Player selection and song selection from browse list.

The change constructs the following (from lower to upper protocol
layers):
1. AVCTP Browse (bta/ & stack/)
                -- Connection Handling
                -- Constructing browse commands
                -- Parsing browse responses
2. AVRCP  (btif/)
                -- JNI interaction/API
                -- Connection handling to Java
                -- Delegating request and responses to Java

Bug: 28791287
Change-Id: Ibc97ded93cb9c469778ea1e37733390d561cd4cd
(cherry picked from commit 9ea8d07c9286a1f4d338dd64ee02266e324d28e5)