- update default httpd.conf:
    clarify the comments on AddDefaultCharset usage (#135821)
    remove all the AddCharset default extensions
    don't load mod_imap by default
    synch with upstream 2.0.53 httpd-std.conf
    - remove htsslpass
    - mod_ssl: set user from SSLUserName in access hook (upstream #31418)
    - htdigest: fix permissions of created files (upstream #33765)