Spring Security Added

Spring Security has been incorporated into the system, providing enhanced security features.
Basic authentication has been implemented, ensuring secure user authentication.
One entity, previously known as "Author," has undergone changes in its fields.
The table related to the Authors entity has been modified, with new columns added.
The Author entity has been renamed to "User," and an enumeration has been introduced to define the roles of each user.
Both in-memory authentication and JDBC authentication mechanisms have been added, offering multiple options for user authentication.
A new filter added.