Unify output format for ODAHU Training Service

[viravit]

ODAHU training service can produce models in different formats:

• Extended old version of MLFlow format
• GPPI format (ODAHU format)

Each model package format is compatible with particular ODAHU packaging service plugin (packager), so user needs figure out themself compatibility between packagers and supported model package formats.

Let's unify the training service output format so all ODAHU packagers can consume output from any model training job. Check if latest MLFlow format covers most of the cases and if it does let's use it.