Add gobject and wrap it into C++ object

[edcuba]

It looks like its working. We can easily wrap gobjects into C++ classes:
https://github.com/dmach/libdnf-cpp-proof-of-concept/pull/4/files#diff-f7097f793b77120cb16500e024ce6988R117

Or just use them on their own:
https://github.com/dmach/libdnf-cpp-proof-of-concept/pull/4/files#diff-f7097f793b77120cb16500e024ce6988R16

[dmach]

Could you move swdbpackage into a different place?
It represents a database record rather than an actual package.

Following structure would be ideal:

• libdnf
  • swdb.h (top-level header for swdb: #include "swdb/package.h" etc.)
  • swdb
    • package.h
    • package.c

[edcuba]

I moved the gobjects, what about the C++ wrappers?
Should I keep them in package.cpp or better create a separate header/source for wrapping these objects? I guess it could be placed in swdb.hpp.

[edcuba]

@dmach Fixed