Add support for custom filenames for archive files

The -o option for recon/exec now supports a parameter for supplying a custom
filename.
Rename ctrl_shell func to shell
Minor fixes, help function

Move all help printing into dedicated function to not clutter up the
main shell function.
Add exfiltration capabilities

Can now use the `exfil' command to pull back files from target onto
server.
Rename to poet
Update name
Further partition output directory

Segregate archived files based on the command they were produced by
(exec, recon, exfil)