CarpetX: Added option to exclude boundaries in 1D tsv output

[lucass-carneiro]

This PR adds the option to exclude boundaries when saving 1D TSV files

[eschnett]

Does this output just the outer boundary points, or does it output ghost points as well? If so, the documentation should be changed.

[lucass-carneiro]

Does this output just the outer boundary points, or does it output ghost points as well? If so, the documentation should be changed.

As far as my understanding goes, TSV files don't output ghosts, only outer boundaries (points starting with negative indices and extending beyond the cell size). This parameter excludes the outer boundaries in TSV output data.