[Roadmap] Allow to add customizable persona

[kevinarch]

Why
Currently, there is no option to define reusable personas. As a workaround, I create a new chat with a custom prompt and mark it as a "Favorite" to reuse it later. However, this approach has some limitations.

Description
Adding a separate section in the settings(?) to manage custom personas. This feature would enable users to create, edit, and remove personas as needed.

Requirements
To enhance flexibility, it would be beneficial to allow users to set a persona's avatar using either a remote image URI or an emoji

[enricoros]

Agree it's important, and also widely covered in the Roadmap: https://github.com/users/enricoros/projects/4/views/2?filterQuery=is%3Aissue%2Cpr+label%3A%22New+Personas%22

Marking as duplicate of #35