Clean Up Code from Web UI Experiment

[azriel91]

Tasks:

• Flow::item_locations_and_interactions_current needs to correctly hide nodes/edges if the nodes are from item_interactions_example.
• OutcomeInfoGraphCalculator::calculate_* needs to compute edges.
• Add tests for ParamsSpec::resolve{_partial} InMemory with different ValueResolutionCtxs.
• A number of incorrect <Transition> / leptos resource usages in flow_graph.rs. See browser console for errors.
• Is the ItemLocation merging correct? What if we had A and C, A and B, and B and C ancestors. Should we merge them into A, B, C? Because someone else's B may actually represent a different concept, which just happens to have the same ItemLocation values. Source files concerned: Flow, OutcomeInfoGraphCalculator.
• Render markdown -- see WebiServer receiving WebUiUpdate::Markdown.
• Unit tests for Progress, and OutputWrite impls -- sending CmdBlockStart.
• Move CmdBlockItemInteractionType / all of peace_core::progress to new peace_progress_model crate.
• Save Generated::Values in states_goal, and not overwrite it during state_goal_try_exec. See 3a74056.
• State maybe should be split into the State that represents contents, and the Location where it resides. Diff doesn't care about the Location between current vs goal, but it does care if the location changes for the dest param, e.g. destination path of where to store it changes. i.e. params_prev.dest() != params_next.dest() is a difference and the file needs to move, but params.dest() vs params.source() being different, with contents being the same, is not a state_diff() difference.
• Move Flow into flow_rt crate.
• Add tests for ParamsMergeExt generated code -- structs and enums.

Originally posted by @azriel91 in #182 (comment)