- Implemented functionality to create, upload, download, and delete attachments associated with ciphers.
- Introduced a new `attachments` module and updated the database schema to include an `attachments` table.
- Enhanced the API routes to handle attachment operations, including legacy support.
- Updated the README and configuration files to reflect the new attachment feature and its usage.
- Added new fields for Argon2 parameters (kdf_memory, kdf_parallelism) in the users table and related SQL migration.
- Updated API routes and handlers to support changing KDF settings.
- Enhanced KDF validation logic to accommodate both PBKDF2 and Argon2.
- Modified user registration and prelogin responses to include Argon2 parameters.
- Updated relevant data structures to reflect new KDF settings.
