Encrypted Field for Cloud

Adding a custom field of this this type to a project enables the following features:

- Users creating or editing issues are able to encrypt values (client side, such that the confidential information is never sent to the server) and decrypt later (when editing the issue).

- Decrypt the data and/or re-encrypt other information in the field when editing the issue

- Users without edit-permission can decrypt the encrypted data when viewing the issue (and hide it)

- The information is never sent to the server (when encrypted or when shown decrypted)