[FEATURE] Automatic Transcription of Differential Equations

[pulsipher]

Describe the feature you'd like
Automatically transcribe models with ODEs and/or PDEs via TranscriptionOpt using finite difference, orthogonal collocation, and/or integrals.

Does this pertain to a particular class of problems/techniques? If so explain.
This is relevant to dynamic and space-time problems.

Describe what you currently do about this
Currently users have to manually encode such methods via point variables.

Additional context
This should be extendable to allow for a wide range of user-defined methods. This primarily should have to deal adding additional supports if needed (e.g., interior points) and with forming linking
constraints to properly define the derivative variables.

Also this needs to be done in conjunction with #9.

[pulsipher]

These methods should will be located in derivative_expansion (think of better name) that will be within InfiniteOpt that outputs the appropriate set of auxiliary reformation equations using appropriate reduced/point variables/derivatives. Perhaps, this could return a vector of constraint objects (not yet added to the model) and use the make_point_variable_ref and make_reduced_variable_ref from measure expansion (these methods will allow for point/reduced variables at transcription that are not added to the infinite model). Note, with #9 we will need to add like methods for derivatives.