Encrypted check breaks storing of PGP keys

[hiasr]

The current implementation only encrypts a field when it is not armored, due to the is_encrypted check.
This causes difficult to debug issues when trying to store keys, which also start with ----BEGIN but of course are not encrypted.

What is the reason for this check? I would think the most logical behaviour is to always encrypt, if users want to encrypt the data themselves they should use the normal Django fields.
Would be willing to contribute but wanted to know if this change is wanted!