Separate out Go tasks and Go worker in to separate processes (#56079)

This change is a big one (too big if I'm honest, but I cannot for the life of
my think of a way of usefully separating this out) to the architecture of how
the Go-SDk works.

Previously the tasks ("the registry") and the executor would be compiled in to
a single binary, and the go worker could only execute Tasks for a single DAG
version. Neither of these were good properties for production-ready code.

This changes the architecture as follows

```
┌──────────────────────┐     ┌───────────────────────────┐
│ airflow-go-worker    │     │ DAG Bundle Plugin Binary  │
│                      │     │                           │
│ ┌──────────────────┐ │     │ ┌─────────────────────┐   │
│ │ Celery Consumer  │ │     │ │ Task Registry       │   │
│ └────────┬─────────┘ │     │ └─────────┬───────────┘   │
│          │           │     │           │               │
│ ┌────────▼─────────┐ │     │ ┌─────────▼───────────┐   │
│ │ Plugin Client    │◄┼─────┼─┤ Plugin Server       │   │
│ └──────────────────┘ │     │ └─────────────────────┘   │
│                      │     │                           │
└──────────────────────┘     └───────────────────────────┘
```

The `airflow-go-worker` in this diagram is the Executor Worker -- i.e. it gets
messages off a Celery queue and then hands off the Workload to another
process, communication to which is handled via Hashicorp's go-plugin.

Go-plugin is a well tested library used to implement both Terraform Providers
and Granfana plugins.

The package layout of this change is roughly as follows:

- `bundle/bundlev1/bundlev1server`

  The server/bundle side of the plugin interface.

  Contains the main entrypoint that bundles should call, `Serve()`

- `bundle/bundlev1`

  The bundle-side types and interfaces. This is mostly what dag bundles will
  import to register tasks:

  ```go
  import "github.com/apache/airflow/go-sdk/bundle/bundlev1"

  // ...

  func (m *myBundle) RegisterDags(dagbag bundlev1.Registry) error {
      tutorial_dag := bundle.AddDag("tutorial_dag")
      tutorial_dag.AddTask(extract)
      tutorial_dag.AddTask(transform)
      tutorial_dag.AddTask(load)
  }
  ```

- `internal/protov1`

  The protobuf source and generated files, shared between clients and servers.

- `pkg/bundles/shared`

  Config and code shared between clients and servers that is
  global/non-versioned/multi-version-aware.

- `bundle/bundlev1/bundlev1client`

  The client used to speak to v1 Bundle binaries.
---------

Co-authored-by: Kaxil Naik <kaxilnaik@gmail.com>
Co-authored-by: Amogh Desai <amoghrajesh1999@gmail.com>