Support <ruby> directives in Meterpreter rc scripts

[zeroSteiner]

Per @egypt's request in #8702, this PR adds support to Meterpreter's resource command to process <ruby> directives. This also adds tab completion support for an option meterpreter sub directory under the existing resource scripts directory. This is because the context of the two are different enough that it would be beneficial to keep them separate as alot of the commands would not work in both contexts.

Alot of the code is copy and pasted, if anyone has a suggestion on where it could be placed to be reused just let me know and I'll get it all refactored.

Verification

List the steps needed to make sure this thing works

• Create a resource script at ~/.msf4/scripts/resource/meterpreter/foo.rc with the following contents

sysinfo
<ruby>
$stderr.puts("session.platform: #{session.platform}, framework: #{framework}")
</ruby>

• Start msfconsole
• Get a meterpreter session some how
• Type resource then try and tab complete the meterpreter rc scripts
• See foo.rc displayed in the completion suggestions
• Run resource foo.rc and see:
  • The sysinfo output, showing normal commands are still run
  • The session platform, showing that the session object is exposed

Example Output

meterpreter > resource 
resource .dockerignore                 resource .ruby-gemset                  resource CONTRIBUTING.md               resource LICENSE                       resource foo.rc                        resource msfupdate
resource .gitignore                    resource .ruby-version                 resource COPYING                       resource LICENSE_GEMS                  resource metasploit-framework.gemspec  resource msfvenom
resource .gitmodules                   resource .simplecov                    resource Dockerfile                    resource README.md                     resource msfconsole                    
resource .mailmap                      resource .travis.yml                   resource Gemfile                       resource Rakefile                      resource msfd                          
resource .rspec                        resource .yardopts                     resource Gemfile.local.example         resource Vagrantfile                   resource msfrpc                        
resource .rubocop.yml                  resource CODE_OF_CONDUCT.md            resource Gemfile.lock                  resource docker-compose.yml            resource msfrpcd                       
meterpreter > resource foo.rc 
[*] Processing /home/steiner/.msf4/scripts/resource/meterpreter/foo.rc for ERB directives.
resource (/home/steiner/.msf4/scripts/resource/meterpreter/foo.rc)> sysinfo
Computer        : localhost.localdomain
OS              : Linux 4.13.5-200.fc26.x86_64 #1 SMP Thu Oct 5 16:53:13 UTC 2017
Architecture    : x64
System Language : en_US
Meterpreter     : python/linux
[*] resource (/home/steiner/.msf4/scripts/resource/meterpreter/foo.rc)> Ruby Code (79 bytes)
session.platform: linux, framework: #<Msf::Framework:0x000000000560a630>
meterpreter > 

[wvu]

You rock. Thanks for implementing this.

[wvu]

I believe when we found this and tried to move load_resource, we didn't find an immediately ideal place for it. What you've done is fine. There's already a nauseating amount of crossover between command dispatchers, though...

[bwatters-r7]

Release Notes

This PR adds support for meterpreter's resource command to support rc scripts with inline ruby and ERB to make resource scripts run through meterpreter more powerful.