Ada Utility Library 2.7.0

• New package Util.Files.Walk to iterate over directory trees and honor .gitignore
• Add support for custom log formatter (allow to translate log messages, filter messages, ...)
• Feature #48: Change the log time from UTC to Local Time (configurable)
• Fix #49: Perf report generates incorrect XML title attributes
• Fix #50: 128Bit AES-CTR Encoding doesn't work (thanks Adam Jasinski)
• Fix #53: Executor does not always stop the worker tasks
• Used spdx-tool to use SPDX-License-Identifier in headers