- define notification names
- move "post notification" to PasswordStore (todo: move "search" and the one for "show folder switch")
- "erase" and "reset" also post the "passwordStoreUpdated" notification
- Update logic: Only fields otp_secret and otp_type are required for TOTP. Only fields otp_secret, otp_type and otp_counter are required for HOTP. Other fields (i.e., otp_algorithm, otp_digits, otp_period) are optional.
- Support HOTP: (1) passwords are initially concealed; (2) "tap->next" generates a new password and commits the updated password file automatically
