Update changelog.md with 1.58.0 and 1.59.0 release notes.
Update changelog.md with 1.58.0 and 1.59.0 release notes.

telstra/open-kilda,telstra/open-kilda,jonvestal/open-kilda,jonvestal/open-kilda,jonvestal/open-kilda,telstra/open-kilda,telstra/open-kilda,telstra/open-kilda,jonvestal/open-kilda,telstra/open-kilda,telstra/open-kilda,jonvestal/open-kilda