ParametricMCPs 0.2 Breaking Changes

[lassepe]

We are planning a new release with the follow breaking changes

New High-Level Workflow

• As before, the user constructs an MCP from F, lb, ub.
• Unlike before, the MCP can be converted into different transcriptions
• We now support multiple solvers. A solver is generated by handing an MCP transcription to solver constructor
• The solver is called as solver(θ[; initial_guess]). It's output format depends on the input format
• TODO: think about this --- maybe we need a MCPVariables type that is associated with each problem format

Features to Implement

Must have

• There is a new abstract problem type AbstractParametricMCP with a nominal concrete version that only takes in F(z,\theta), lb, ub and no gradients. Gradients are now considered solver-internals
• Beyond the nominal problem type, we provide different transcription types + conversion scheme; e.g G-H-slack formulation.
• There will be a AbstractMCPSolution type: each concrete problem struct has a concrete solution struct associated with it; we provide conversions

Maybe

• The user can specify which output format they want