Update plugin handling and enhance file input functionality - Added validation for existing plugins during updates to ensure they exist before proceeding, improving error handling and user feedback. - Preserved deployment status when updating plugins to maintain consistency in their configurations. - Introduced a new `FileValue` struct for handling file-based x-source values, including validation and volume mount configurations. - Enhanced the `DeploymentModal` to support file input, allowing users to upload or paste file contents directly, improving usability. - Updated Swagger documentation to reflect changes in API endpoints and request structures. These changes enhance the overall functionality and user experience when managing plugins and file inputs within the application. Signed-off-by: dviejokfs <dviejo@kfs.es>