Update to synch up with changes inte agent-api module.

[alexheifetz]

This pull request makes changes to the WriteAndReviewAgent class to improve the structure and functionality of the Persona creation process by updating imports and adding new parameters to the Persona.create method. The most important updates include switching to a new package for the Persona class, using the Companion object for method access, and introducing a new parameter, PromptContributionLocation.

Updates to Persona creation:

• Updated the import for the Persona class to use the com.embabel.agent.prompt.persona package instead of com.embabel.agent.prompt for better organization.
• Modified the Persona.create method calls to use the Companion object for accessing the create method, aligning with Kotlin conventions.
• Added a new parameter, PromptContributionLocation.BEGINNING, to the Persona.create method calls for both WRITER and REVIEWER, enabling specification of where the prompt contribution should occur.