* src/storage/phobos_file.cc: need to set xd_objid to NULL to avoid double free

* src/storage/phobos_file.hexplicit copy constructors to avoid double free of xd_objid
* tests: reflect meta data change to std::map from std::vector
* run Clang Format
* resolve Clang Tidy warnings
* add Gitlab-CI
* use fiphoboserver docker image
* update DockerHub image with Doxygen requirements
* CI: Clang Format job
* CI: Clang Tidy job
* CI: Doxygen build job
* CI: Unit Tests job
4 jobs for 8-ci in 4 minutes and 33 seconds (queued for 2 seconds)