(Refactor) Use native laravel encrypted cast

[Roardom]

Questions:

What should be done if a value fails to decrypt during the migration (e.g. if the key was rotated and the old key no longer exists under APP_PREVIOUS_KEYS)? Right now the migration fails.

Possible options:

• Don't migrate the record
• Save an empty string (encrypted)
• Save The value could not be decrypted (encrypted)
• Delete the record

Note that laravel's native encrypted cast will throw an exception causing a 500 error if decryption fails instead of falling back to The value could not be decrypted like the current trait.

[what-the-diff]

PR Summary

• Encryption Handling Overhaul for Donation and Seedbox Models
  Removal of Encryptable trait and adjustments to data encryption handling.
• Type Change of 'transaction' Attribute in Donation Model
  Type updated to 'encrypted' indicating a shift in encryption methodology.
• 'ip' Attribute Designated as 'Encrypted' in Seedbox Model
  Change reflective of the new encryption standards.
• Deletion of Encryptable Trait
  No longer needed after encryption processes refactoring.
• Inclusion of New Database Migration
  New file to re-encrypt existing 'transaction' and 'ip' data in respective tables.
• MySQL Schema Updated
  New migration file included in the list of applied migrations.
• Model Documentation Updated
  Adjustments to encapsulate changes to encryption standards and attributes.