build: Eliminate cutils/sockets dependencies from system/bt

Eliminate cutils/sockets dependencies by pulling sources files from
core/libcutils into osi/.
   - Pulled source files from cutils/ into osi/ and modified GN files and
     Android.mk
   - Updated includes to use the headers in osi/ and removed unused/duplicated
     headers.
   - Renamed the functions of osi/sockets and updated wherever they are called
     to avoid usign symbols from cutils/sockets, since other cutils
     dependencies have not been eliminated yet.

Bug: 21667795
Change-Id: I3dd4371d585f120d97ac0433ab1f35edb820dbb9
15 files changed