cmd, core, ethdb, node: move chain freezer one folder deeper (#25487)

* cmd, core, ethdb, node: create chain freezer in a sub folder

* core/rawdb: remove unused code

* core, ethdb, node: add AncientDatadir API back

* cmd, core: extend freezer info dump for sub-ancient-store

* core/rawdb: rework freezer inspector

* core/rawdb: address comments from Peter

* core/rawdb: fix build issue

ethdb/database.go

@@ -142,7 +142,9 @@ type AncientWriteOp interface {
 
 // AncientStater wraps the Stat method of a backing data store.
 type AncientStater interface {
-	// AncientDatadir returns the root directory path of the ancient store.
+	// AncientDatadir returns the path of root ancient directory. Empty string
+	// will be returned if ancient store is not enabled at all. The returned
+	// path can be used to construct the path of other freezers.
 	AncientDatadir() (string, error)
 }
 
@@ -172,7 +174,6 @@ type Stater interface {
 type AncientStore interface {
 	AncientReader
 	AncientWriter
-	AncientStater
 	io.Closer
 }