postfix: Update to version 3.8.4 + prevent smtp smuggling

postfix: Update to version 3.8.4 + prevent smtp smuggling

- Update from version 3.8.3 to 3.8.4
- Update of rootfile not required
- Permanent fix for smtp smuggling will be in version 3.9. However the fix has been
   backported into version 3.8.4 but with the default for the parameter of "no".
- This patch sets the defaults for all the main.cf parameters highlighted by Wietse
   Venema in http://www.postfix.org/smtp-smuggling.html
- Additionally the implementation of smtpd_forbid_bare_newline = yes has been added to
   the install.sh pak for postfix so that it will be included into any main.cf file being
   restored from backup. This parameter is available for the first time in 3.8.4 so will
   not be in any backup prior to this release and can therefore be safely applied to
   restored versions of main.cf.
- This fix in install.sh will be able to be removed when version 3.9 is released early
   in 2024 as the default for that parameter in that version onwards will then be "yes"
- Changelog
    3.8.4
	Security: with "smtpd_forbid_bare_newline = yes" (default
	 "no" for Postfix < 3.9), reply with "Error: bare <LF>
	 received" and disconnect when an SMTP client sends a line
	 ending in <LF>, violating the RFC 5321 requirement that
	 lines must end in <CR><LF>. This prevents SMTP smuggling
	 attacks that target a recipient at a Postfix server. For
	 backwards compatibility, local clients are excluded by
	 default with "smtpd_forbid_bare_newline_exclusions =
	 $mynetworks". Files: mantools/postlink, proto/postconf.proto,
	 global/mail_params.h, global/smtp_stream.c, global/smtp_stream.h,
	 smtpd/smtpd.c.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>