PMG 7 ClamAV RAR scan support

By default PMG 7 use clamav as it default antivirus scanner and also based on Debian as it base OS.
Due to RAR format is a proprietary file-format and Debian have policy to move all non-free package to the non-free repository.
Further more, PMG do not enable the non-free repository by default so it could cause problem detecting virus in RAR format.

root@pmg:~# clamscan eicar_com.zip
/root/eicar_com.zip: Win.Test.EICAR_HDB-1 FOUND

----------- SCAN SUMMARY -----------
Known viruses: 8605212
Engine version: 0.103.5
Scanned directories: 0
Scanned files: 1
Infected files: 1
Data scanned: 0.00 MB
Data read: 0.00 MB (ratio 0.00:1)
Time: 16.637 sec (0 m 16 s)
Start Date: 2022:02:06 17:25:59
End Date:   2022:02:06 17:26:16

root@pmg:~# clamscan IMG-78293792.rar
/root/IMG-78293792.rar: OK

----------- SCAN SUMMARY -----------
Known viruses: 8605212
Engine version: 0.103.5
Scanned directories: 0
Scanned files: 1
Infected files: 0
Data scanned: 0.34 MB
Data read: 0.33 MB (ratio 1.05:1)
Time: 15.134 sec (0 m 15 s)
Start Date: 2022:02:06 17:26:49
End Date:   2022:02:06 17:27:05

1. To enable non-free repository, add the non-free repository to your /etc/apt/sources.list file.

root@pmg:~# cat /etc/apt/sources.list
deb http://ftp.debian.org/debian bullseye main contrib non-free

deb http://ftp.debian.org/debian bullseye-updates main contrib non-free

# security updates

deb http://security.debian.org bullseye-security main contrib non-free

2. Update repository and install libclamunrar package.

apt-get update
apt-get install libclamunrar

3. Run clamascan on the rar virus again.

root@pmg:~# clamscan IMG-78293792.rar
/root/IMG-78293792.rar: Win.Packed.Pwsx-9936836-0 FOUND

----------- SCAN SUMMARY -----------
Known viruses: 8605212
Engine version: 0.103.5
Scanned directories: 0
Scanned files: 1
Infected files: 1
Data scanned: 0.36 MB
Data read: 0.33 MB (ratio 1.10:1)
Time: 14.799 sec (0 m 14 s)
Start Date: 2022:02:06 17:34:27
End Date:   2022:02:06 17:34:42