Remove most old example code

[PhilipFackler]

Description

Remove example code that duplicates what the DynamicSimulation app does

Closes #390 (indirectly)

Proposed changes

• Add existing "tiny" cases to CaseFormatTests to check JSON parser
• Remove example source code
• Create ref.csv files for cases that were still using the .hpp data
• Create .solver.json files where needed
• Update tests and input/output files to use same naming conventions

Checklist

• All tests pass.
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• [N/A] The new code follows GridKit™ style guidelines.
• [N/A] There are unit tests for the new code.
• [N/A] The new code is documented.
• The feature branch is rebased with respect to the target branch.
• [N/A] I have updated CHANGELOG.md to reflect the changes in this PR. If this is a minor PR that is part of a larger fix already included in the file, state so.

[pelesh]

Rather than removing examples, I would turn them into integration tests. Some of those examples set up GridKit apps without parser and thus verify that the system composer generates system models correctly and integrates well with solvers.

[PhilipFackler]

Rather than removing examples, I would turn them into integration tests. Some of those examples set up GridKit apps without parser and thus verify that the system composer generates system models correctly and integrates well with solvers.

I added them in CaseFormatTests to compare parsing results with the direct assignment that was in those examples. I thought this was what we had discussed before, but maybe I misunderstood. Do you want something more than that?