Add the option to use a pa11y.json

[Eduardo-Morales-Alberti]

Pally allows the use of a configuration file https://github.com/pa11y/pa11y?tab=readme-ov-file#command-line-configuration
Allows users to override this configuration creating the file.

Currently, the command gets the default config.json

/app/node_modules/.bin/pa11y -c /app/config/config.json "$@"