This patch adds workflow files for ci:

[sync.yml]
  - runs every 30 mins.
  - sync repo with upstream repo and rebase workflow branch to tip of
    master.
  - creates PR after reading patches from patchwork.kernel.org

[ci.yml]
  - Tests the following checks:
    - checkpatch
    - gitlint
    - make
    - make check

[code_scan.yml]
    - Static code checker: Coverity and Clang
    - Coverity: Submit the result to the coverity website
    - Clang Code Scan: Send email with result file to the internal team

To simplify the history, new change will amend to this patch without
creating new patch.

Change 44d3f67 since to have introduced
quite a few bugs related to device_is_connected return true which
prevents proper cleanup of connection.

Fixes: bluez#774
Fixes: bluez#778
Fixes: bluez#783
Fixes: bluez#784