testing/profanity: disable gpg support

The goal of this removal is to:
- Discourage people from using gpg (no forward secrecy, no deniability, …) for chat, and nudging them towards better solutions like OTR, or even better OMEMO
- Get rid of the gpg, gpg-agent, gpgsm, gpgme, gnupg-gpgconf, libgpg-error, libassuan, … dependencies
- Be closer to Alpine's minimalism mantra

GPG support in XMPP is spotty at best: xep-0373 is experimental, xep-0374 is
deferred, xep-0027 is obsolete: implementation into production client is
therein not recommended.
8 jobs for !28747 with no_gpg_profanity in 2 minutes and 29 seconds (queued for 4 seconds)
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