[#804] ape: Implement boltdb storage for local overrides

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

pkg/ape/chainbase/interface.go

@@ -0,0 +1,22 @@
+package chainbase
+
+import (
+	"context"
+
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/engine"
+)
+
+// DatabaseCore interface provides methods to initialize and manage local override storage
+// as database.
+type DatabaseCore interface {
+	Init() error
+	Open(context.Context) error
+	Close() error
+}
+
+// LocalOverrideDatabase interface provides methods to manage local override storage
+// as database and as the APE's local override storage.
+type LocalOverrideDatabase interface {
+	DatabaseCore
+	engine.LocalOverrideStorage
+}