Provide tools to analyze the files in a database.

Recently, I tried to use CodeQL to analyze my project, and all the steps succeeded without any warnings. However, after running some queries I realized that it was missing most of the files.

As a user, it would be nice to be able to list the files that are included in the database with just a command.

After talking with @adityasharad , he suggested using a simple query that just lists all the files:

```
/**
* @description "List all the files"
* @id debug.listfiles
* @kind problem
* @name list-files
* @tags maintanability
* @problem.severity recommendation
**/
import cpp

from File f
select f, "This file is in the repo"
```

It would be nice to have something like that built into the application.

Comienza con la CodeQL CLI y la consulta sencilla `debug.listfiles` mostrada en el issue; compara su salida con los archivos incluidos en la base de datos. Define un comando integrado que liste esos archivos y verifica que exponga archivos que actualmente se omiten del análisis.

Escrito por el modelo de indexación a partir del texto del issue.