controller: remove remaining parts of the controller

Removes all references to the controller and moves the remaining
sections of code to other packages.

Processes has been moved to monitor where it is used and the data
structs have been removed so buildflags is used directly. The controller
build function has been moved to the commands package.

Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com>

util/buildflags/export.go

@@ -9,7 +9,6 @@ import (
 	"strings"
 
 	"github.com/containerd/platforms"
-	controllerapi "github.com/docker/buildx/controller/pb"
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
@@ -38,18 +37,6 @@ func (e Exports) Normalize() Exports {
 	return removeDupes(e)
 }
 
-func (e Exports) ToPB() []*controllerapi.ExportEntry {
-	if len(e) == 0 {
-		return nil
-	}
-
-	entries := make([]*controllerapi.ExportEntry, len(e))
-	for i, entry := range e {
-		entries[i] = entry.ToPB()
-	}
-	return entries
-}
-
 type ExportEntry struct {
 	Type        string            `json:"type"`
 	Attrs       map[string]string `json:"attrs,omitempty"`
@@ -77,14 +64,6 @@ func (e *ExportEntry) String() string {
 	return b.String()
 }
 
-func (e *ExportEntry) ToPB() *controllerapi.ExportEntry {
-	return &controllerapi.ExportEntry{
-		Type:        e.Type,
-		Attrs:       maps.Clone(e.Attrs),
-		Destination: e.Destination,
-	}
-}
-
 func (e *ExportEntry) MarshalJSON() ([]byte, error) {
 	m := maps.Clone(e.Attrs)
 	if m == nil {
@@ -164,12 +143,12 @@ func (e *ExportEntry) validate() error {
 	return nil
 }
 
-func ParseExports(inp []string) ([]*controllerapi.ExportEntry, error) {
+func ParseExports(inp []string) ([]*ExportEntry, error) {
 	if len(inp) == 0 {
 		return nil, nil
 	}
 
-	export := make(Exports, 0, len(inp))
+	exports := make(Exports, 0, len(inp))
 	for _, s := range inp {
 		if s == "" {
 			continue
@@ -179,9 +158,9 @@ func ParseExports(inp []string) ([]*controllerapi.ExportEntry, error) {
 		if err := out.UnmarshalText([]byte(s)); err != nil {
 			return nil, err
 		}
-		export = append(export, &out)
+		exports = append(exports, &out)
 	}
-	return export.ToPB(), nil
+	return exports, nil
 }
 
 func ParseAnnotations(inp []string) (map[exptypes.AnnotationKey]string, error) {