Definitions:
* Database Key - Cryptographic hash used to perform encrypt/decrypt of the database.
* Database Credentials - User facing term to refer to the collection of Password, Key File, and/or Hardware Key used to derive the Database Key.
Changes:
* Remove the term "master" and "key" from the user's lexicon and clarify the code base based on the definitions above.
* Clean up wording in the UI to be clearer to the end user.
