[installer] master.cf changed on Debian 12 aka Bookworm
## Summary
master.cf has changed on Debian 12 aka Bookworm. Thus the change of maildrop service in postfix master.cf does not work anymore.
## Steps to reproduce
1. (Auto)Install ISPConfig on Debian 12 aka Bookworm
2. Check /etc/postfix/master.cf
```
maildrop unix - n n - - pipe
flags=DRXhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
```
## Correct behaviour
```
maildrop unix - n n - - pipe
flags=DRXhu user=vmail argv=/usr/bin/maildrop -d vmail ${extension} ${recipient} ${user} ${nexthop} ${sender}
```
## Environment
Server OS + version: Debian 12 \
ISPConfig version: 3.2dev \
Software version of the related software:
```
postfix 3.7.6-0+deb12u2
```
## Proposed fix
Lines 1365-1367 in install/lib/installer_base.lib.php
```
$content = preg_replace('/flags=(DRX?hu) user=vmail argv=\/usr\/bin\/maildrop -d \${recipient}/',
'flags=$1 user='.$cf['vmail_username'].' argv=/usr/bin/maildrop -d '.$cf['vmail_username'].' \${extension} \${recipient} \${user} \${nexthop} \${sender}',
$content);
```
issue