split: replace internal packages with images library

Remove all the internal package that are now in the
github.com/osbuild/images package and vendor it.

A new function in internal/blueprint/ converts from an osbuild-composer
blueprint to an images blueprint.  This is necessary for keeping the
blueprint implementation in both packages.  In the future, the images
package will change the blueprint (and most likely rename it) and it
will only be part of the osbuild-composer internals and interface.  The
Convert() function will be responsible for converting the blueprint into
the new configuration object.

vendor/github.com/osbuild/images/pkg/disk/partition.go

@@ -0,0 +1,87 @@
+package disk
+
+import (
+	"fmt"
+)
+
+type Partition struct {
+	Start    uint64 // Start of the partition in bytes
+	Size     uint64 // Size of the partition in bytes
+	Type     string // Partition type, e.g. 0x83 for MBR or a UUID for gpt
+	Bootable bool   // `Legacy BIOS bootable` (GPT) or `active` (DOS) flag
+
+	// ID of the partition, dos doesn't use traditional UUIDs, therefore this
+	// is just a string.
+	UUID string
+
+	// If nil, the partition is raw; It doesn't contain a payload.
+	Payload Entity
+}
+
+func (p *Partition) IsContainer() bool {
+	return true
+}
+
+func (p *Partition) Clone() Entity {
+	if p == nil {
+		return nil
+	}
+
+	partition := &Partition{
+		Start:    p.Start,
+		Size:     p.Size,
+		Type:     p.Type,
+		Bootable: p.Bootable,
+		UUID:     p.UUID,
+	}
+
+	if p.Payload != nil {
+		partition.Payload = p.Payload.Clone()
+	}
+
+	return partition
+}
+
+func (pt *Partition) GetItemCount() uint {
+	if pt == nil || pt.Payload == nil {
+		return 0
+	}
+	return 1
+}
+
+func (p *Partition) GetChild(n uint) Entity {
+	if n != 0 {
+		panic(fmt.Sprintf("invalid child index for Partition: %d != 0", n))
+	}
+	return p.Payload
+}
+
+func (p *Partition) GetSize() uint64 {
+	return p.Size
+}
+
+// Ensure the partition has at least the given size. Will do nothing
+// if the partition is already larger. Returns if the size changed.
+func (p *Partition) EnsureSize(s uint64) bool {
+	if s > p.Size {
+		p.Size = s
+		return true
+	}
+	return false
+}
+
+func (p *Partition) IsBIOSBoot() bool {
+	if p == nil {
+		return false
+	}
+
+	return p.Type == BIOSBootPartitionGUID
+}
+
+func (p *Partition) IsPReP() bool {
+	if p == nil {
+		return false
+	}
+
+	return p.Type == "41" || p.Type == PRePartitionGUID
+}