fix: make string utils avail externally

Author: arturshadnik

internal/utils/strings/strings.go renamed to pkg/util/strings.go

@@ -1,5 +1,5 @@
-// Package strings contains utility functions for working with strings.
-package strings
+// Package util contains utility functions for working with strings.
+package util
 
 import "strings"
 

internal/utils/strings/strings_test.go renamed to pkg/util/strings_test.go

@@ -1,4 +1,4 @@
-package strings
+package util
 
 import (
 	"slices"