Simplify runtime code by removing layers of abstraction

- Remove intermediary types `Component`, `Script`, `Op`, `mount`: just use
  `cc.Value` directly
- Remove `Executable` interface.
- Execute llb code with a simple concrete type `Pipeline`
- Analyze llb code with a simple utility `Analyze`

Signed-off-by: Solomon Hykes <sh.github.6811@hykes.org>

dagger/types.go

@@ -1,38 +1,13 @@
 package dagger
 
 import (
-	"context"
-	"fmt"
 	"os"
 
 	cueflow "cuelang.org/go/tools/flow"
-
-	"dagger.cloud/go/dagger/cc"
 )
 
 var ErrNotExist = os.ErrNotExist
 
-// Implemented by Component, Script, Op
-type Executable interface {
-	Execute(context.Context, FS, *Fillable) (FS, error)
-	Walk(context.Context, func(*Op) error) error
-}
-
-func newExecutable(v *cc.Value) (Executable, error) {
-	// NOTE: here we need full spec validation,
-	//   so we call NewScript, NewComponent, NewOp.
-	if script, err := NewScript(v); err == nil {
-		return script, nil
-	}
-	if component, err := NewComponent(v); err == nil {
-		return component, nil
-	}
-	if op, err := NewOp(v); err == nil {
-		return op, nil
-	}
-	return nil, fmt.Errorf("value is not executable")
-}
-
 // Something which can be filled in-place with a cue value
 type Fillable struct {
 	t *cueflow.Task