Add AudioPortFoundation, AudioPortBase and AudioPortConfigBase.

The purpose of this change is to make a generic AudioPort class that
could be used by vendor.
1. Add AudioPortFoundation and AudioPortBase. AudioPortFoundation
contains generic members of an audio port. AudioPortBase is a template
class that derives from AudioPortFoundation. It takes audio profile
vector as a template parameters. That makes it more feasible to use
customized audio profile stuff as needed. In audio policy, AudioPort
derives from AudioPortBase and contain policy related stuff.
2. Add AudioPortConfigBase. AudioPortConfigBase contains generic members
of an audio port config. AudioPortConfig derives from AudioPortConfigBase
and contains policy related stuff.
3. Use std::string instead of String8 in AudioPort and AudioPortConfig.

Bug: 135621476
Test: CTS for AudioRecord, AudioTrack, AudioManager, RoutingTest
Test: audiopolicy_tests, AudioServiceHostTest
audio smoke test
Test: dumpsys media.audio_policy
Change-Id: I05611b7067c18006660de2c678acd56bdd34010a
Merged-In: I05611b7067c18006660de2c678acd56bdd34010a