Remove the encrypted shell payload and libs

[zeroSteiner]

The encrypted_shell stage broke at some point when mingw changed from version 8 to version 10. You can confirm this by testing the c4e55f1 commit with the Ruby containers ruby:3.1.5-bullseye (mingw 8) and ruby:3.1.5 (mingw 10). The unstaged payload windows/x64/encrypted_shell_reverse_tcp will work with the older mingw but fail with the newer one. Kali is based on Debian, as is the Ruby container, meaning that this payload has been broken in Kali for about 2 and a half years without any reports. It's been broken in Fedora for longer. Since Metasploit v6, Meterpreter has offered built-in AES-encrypted sessions that do not require a database connection. Given that this has been broken for a long time with no reports, and that offering a more robust and intuitive solution for encrypted communications is the priority, it doesn't seem worthwhile to fix it. The reason I noticed this to begin with was encrypted-shell came up while reviewing the session types as part of #21191. I suspect that because the shell type is marked as encrypted-shell and not simply shell, the sessions aren't compatible with post modules that expect to run OS commands, which is why I went to test them in the first place.

Closes #21071

Verification

• Tests all pass
• The payloads are gone