Allow jsonb columns as encrypted targets

[tobyhede]

Allows jsonb columns as well as the cs_encrypted_v1 domain type.

Adds a force to cs_encrypt_v1()

Calling cs_encrypt_v1(true) will skip the schema check before entering the encrypting state.

[auxesis]

Need some docs, please @tobyhede.

[auxesis]

Thanks @tobyhede.

One small suggestion, and one request.

[auxesis]

Thanks for the changes @tobyhede.