Create observation database with r2d2

[aerorahul]

Create a shared database on Orion and Hera for global dump data.

• Start with gdas and gfs streams, later extend to gdasx, etc.
• First handle bufr_d files (see example branch)
• Next prepbufr and nsstbufr
• Identify grib, grib2, grb files
• Identify leftover files.

Each step will need an extension in the yaml file for different obs_type and the python to handle individual obs_type for store and fetch

An example of r2d2 store and fetch for obs_type=bufr_d is provided in the branch feature/example-obs-db