floss: dpkg build script and configs

    - systemd configs
    - dbus configs
    - script to verify dependencies, download, and build
    - build btclient, btmanagerd, btadapterd
    - generate dpkg for debian linux

Bug: 195443545
Bug: 195443539
Test: build the dpkg
Tag: #floss
Change-Id: Iec679ead5fd94abe45476ea7173bbccf67c45bca