This task requires CORE-2476

Allow staff to create private encrypted notes. If an RSA key has been generated, use the public key to encrypt notes. If no key has been generated, display a warning that notes will not be encrypted unless an RSA public private keypair is generated.

• Location of notes could be in a widget on the Dashboard, but open to discussion about placement
• We should be able to tell if a note is encrypted or not, and whether a passphrase is set
• When viewing a note that is encrypted with a passphrase, you must enter the passphrase before it will be descrypted and displayed
• Notes should be similar to client notes, except a detail box will always be shown and not hidden
• Note subjects will not be encrypted, so that they can be displayed in a table
• Store the date the note was created, and last updated
• When viewing a note that is encrypted with a passphrase, show the passphrase box instead of the detail box. When the correct passphrase is entered, display instead the details box with contents decrypted.

NOTE! Client Notes are stored in client_notes table, so maybe this should be staff_notes? Also, it would be nice to have an option on client_notes to encrypt those also. In many cases, I have client notes that I want to encrypt and having them linked to the client is important.