internal/store: iterator over all entries

This is quite convenient for searching the store or printing active instance information.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/store/segment_test.go

@@ -152,7 +152,7 @@ func TestStateEntryHandle(t *testing.T) {
 	})
 }
 
-func TestStoreHandle(t *testing.T) {
+func TestSegmentHandle(t *testing.T) {
 	t.Parallel()
 
 	testCases := []struct {