Use `auto-source-search' instead of `auto-source-user-or-password'.

Use `auto-source-search' instead of `auto-source-user-or-password'.

* mail/smtpmail.el: Autoload `auto-source-search' instead of
`auto-source-user-or-password.
(smtpmail-try-auth-methods): Use it.

* net/imap-hash.el: Autoload `auto-source-search' instead of
`auto-source-user-or-password.
(imap-hash-open-connection): Use it.

* net/tramp-imap.el: Autoload `auto-source-search' instead of
`auto-source-user-or-password.
(tramp-imap-passphrase-callback-function): Use it.

* net/tramp.el (tramp-default-method): Also check if
`auth-source-search' is bound.
(tramp-read-passwd): Use `auth-source-search' instead of
`auto-source-user-or-password'.

* url-parse.el (url-bit-for-url, url-user-for-url)
(url-password-for-url): Use `auto-source-search' instead of
`auto-source-user-or-password'.

* url-auth.el: Autoload `auto-source-search' instead of
`auto-source-user-or-password'.
(url-basic-auth, url-digest-auth, url-do-auth-source-search): Use it.