Deprecate boltdb and cleveldb (#153)

* deprecate boltdb and cleveldb

Closes #143

* add changelog

.changelog/unreleased/features/153-deprecate-boltdb-cleveldb.md

@@ -0,0 +1,2 @@
+- Deprecate boltdb and cleveldb. If you're using either of those, please reach
+  out ([\#153](https://github.com/cometbft/cometbft-db/pull/153))

README.md

@@ -33,14 +33,14 @@ Go 1.22+
   sets, and tests. Used for [IAVL](https://github.com/tendermint/iavl) working
   sets when the pruning strategy allows it.
 
-- **[LevelDB](https://github.com/google/leveldb) [experimental]:** A [Go
+- **[LevelDB](https://github.com/google/leveldb) [DEPRECATED]:** A [Go
   wrapper](https://github.com/jmhodges/levigo) around
   [LevelDB](https://github.com/google/leveldb). Uses LSM-trees for on-disk
   storage, which have good performance for write-heavy workloads, particularly
   on spinning disks, but requires periodic compaction to maintain decent read
   performance and reclaim disk space. Does not support transactions.
 
-- **[BoltDB](https://github.com/etcd-io/bbolt) [experimental]:** A
+- **[BoltDB](https://github.com/etcd-io/bbolt) [DEPRECATED]:** A
   [fork](https://github.com/etcd-io/bbolt) of
   [BoltDB](https://github.com/boltdb/bolt). Uses B+trees for on-disk storage,
   which have good performance for read-heavy workloads and range scans. Supports

boltdb.go

@@ -34,6 +34,8 @@ type BoltDB struct {
 var _ DB = (*BoltDB)(nil)
 
 // NewBoltDB returns a BoltDB with default options.
+//
+// Deprecated: boltdb is deprecated and will be removed in the future.
 func NewBoltDB(name, dir string) (DB, error) {
 	return NewBoltDBWithOpts(name, dir, bbolt.DefaultOptions)
 }

cleveldb.go

@@ -28,6 +28,8 @@ type CLevelDB struct {
 var _ DB = (*CLevelDB)(nil)
 
 // NewCLevelDB creates a new CLevelDB.
+//
+// Deprecated: cleveldb is deprecated and will be removed in the future.
 func NewCLevelDB(name string, dir string) (*CLevelDB, error) {
 	dbPath := filepath.Join(dir, name+".db")