feat: Bloc visualisation tooling

**Description**

A tool that allows the conversion from a given state diagram to a bloc, and ideally, vice-versa (generate a diagram from a given bloc).

**Desired Solution**

An interface (as in human to computer interaction) that allows a given user to model a bloc via a state diagram and generate the appropriate code for it, and vice-versa.

**Alternatives Considered**

It is very open how this should be done. I don't know which interface would suit better. There are many possible options, for example, an IDE extension, a web similar to https://stately.ai/viz, a CLI, etc.

**Additional Context**

You might be asking "Why?"

It is usually a good idea to plan your code. Planning can range from a single line to a bunch of diagrams or more. Hence, one can also plan (drumroll please 🥁) blocs!

The planning strategy for a bloc can vary from one individual to another. Personally, I find that defining the initial state, states, and transitions are always a good way to start. Since blocs are very, very similar to state machines and are deeply inspired by automata theory, whilst planning I tend to draw some state diagrams.

For example the following (very simple and dummy) state diagram:

Could possibly translate to:

```dart
class FooBloc extends Bloc {
FooBloc() : super(FooInitialState()) {
on(_onFooEvent);
}

void _onFooEvent(FooEvent event, Emitter emit) {
if (state is FooInitialState) {
emit(FooFinalState());
}
}
}

class FooEvent {}

abstract class FooState {}

class FooInitialState extends FooState {}

class FooFinalState extends FooState {}
```

In addition, one could also examine a given bloc and produce a state diagram. Computer Scientists are very familiar with state diagrams and generating a state diagram from a given bloc can simplify (and accelerate) the process of comprehending a given bloc.

This might also allow for automation (or other cool stuff) in the feature.