[FEATURE] Enable Connection type keys in compile

[norhan-synnada]

Feature Request

Describe the Feature

Constant, data, discard, jacobian, trainable keys and shapes arguments can be provided as strings or Connection objects to the compile function.

Motivation

User should not be forced to provide only string representations of the connections.

Proposed Solution

Add Connection type handling of the keys in compile and PhysicalModel.

Alternatives Considered

No alternatives, solution is straightforward.

Additional Context

Unnamed runtime data should be checked optionally. Add boolean safe_names argument to the compile function in order to check all runtime data (not any parameters) are named in logical model. This would make providing data and understanding data flow easier to the user if requested.