removed duplicate __serialize and __unserialize

[Schlue]

@ralflang the integration of one of the pull requested caused a duplicate of the new __serialize functions. This pull requests removed these functions.

[what-the-diff]

PR Summary

• Update to .gitignore
  Added .vscode to the .gitignore file to prevent Visual Studio Code settings from being tracked in git.

• Removal of serialization methods
  Consistently removed the __serialize and __unserialize methods across multiple classes in the Horde/Imap/Client directory. This change affects several files, including Base.php, Data/Acl.php, Data/AclRights.php, Data/Capability.php, Data/Envelope.php, Data/Namespace.php, Data/SearchCharset.php, Data/Thread.php, Ids.php, Ids/Map.php, Mailbox.php, Search/Query.php, Url.php and Url/Base.php. This cleanup simplifies the codebase by eliminating these unnecessary or redundant serialization functionalities.

[ralflang]

Seems like we had a duplication between horde master efforts and maintaina-com/FRAMEWORK_6_0 efforts during the long time when both ran in parallel.