core, eth, les, tests, trie: abstract node scheme (#25532)

This PR introduces a node scheme abstraction. The interface is only implemented by `hashScheme` at the moment, but will be extended by `pathScheme` very soon.

Apart from that, a few changes are also included which is worth mentioning:

-  port the changes in the stacktrie, tracking the path prefix of nodes during commit
-  use ethdb.Database for constructing trie.Database. This is not necessary right now, but it is required for path-based used to open reverse diff freezer

trie/database.go

@@ -68,7 +68,7 @@ var (
 // behind this split design is to provide read access to RPC handlers and sync
 // servers even while the trie is executing expensive garbage collection.
 type Database struct {
-	diskdb ethdb.KeyValueStore // Persistent storage for matured trie nodes
+	diskdb ethdb.Database // Persistent storage for matured trie nodes
 
 	cleans  *fastcache.Cache            // GC friendly memory cache of clean node RLPs
 	dirties map[common.Hash]*cachedNode // Data and references relationships of dirty trie nodes
@@ -273,14 +273,14 @@ type Config struct {
 // NewDatabase creates a new trie database to store ephemeral trie content before
 // its written out to disk or garbage collected. No read cache is created, so all
 // data retrievals will hit the underlying disk database.
-func NewDatabase(diskdb ethdb.KeyValueStore) *Database {
+func NewDatabase(diskdb ethdb.Database) *Database {
 	return NewDatabaseWithConfig(diskdb, nil)
 }
 
 // NewDatabaseWithConfig creates a new trie database to store ephemeral trie content
 // before its written out to disk or garbage collected. It also acts as a read cache
 // for nodes loaded from disk.
-func NewDatabaseWithConfig(diskdb ethdb.KeyValueStore, config *Config) *Database {
+func NewDatabaseWithConfig(diskdb ethdb.Database, config *Config) *Database {
 	var cleans *fastcache.Cache
 	if config != nil && config.Cache > 0 {
 		if config.Journal == "" {
@@ -917,3 +917,8 @@ func (db *Database) CommitPreimages() error {
 	}
 	return db.preimages.commit(true)
 }
+
+// Scheme returns the node scheme used in the database.
+func (db *Database) Scheme() NodeScheme {
+	return &hashScheme{}
+}