support datetime + formatting in connectors

[izulin]

Is your feature request related to a problem? Please describe.
Connectors (python connector, jsonlines, kafka...) pass datetime values as str.

Describe the solution you'd like
Add support for:

• formatting auxiliary info in schemas and/or pathway types
• connectors doing basic preprocessing using schema auxiliary info

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.