Add possibility to work with additional features in PatchTSModel

[egoriyaa]

Description

Add possibility to work with additional features in PatchTSModel.

Proposal

• Modify model architecture to handle additional features. Now model supports target only.
  • Read paper for deep understanding.
  • See other libraries which support PatchTST as references.
  • Suggest your own ideas.
• Add support of categorical features, see issue.

Test cases

PatchTSModel works correctly with numeric and categorical additional features.

Additional context

Converted from #343

[egoriyaa]

is blocked by #345