[FR] return all output files from quarto inspect

[cderv]

Discussed in #2378

^{Originally posted by wlandau September 9, 2022}
The targets R package integrates with Quarto via tarchetypes::tar_quarto() for reproducible analysis pipelines. For reproducibility, targets hashes the input and output files from Quarto and uses the hashes to decide whether to run the Quarto document or project. To learn which input and output files to track, tar_quarto() digs through the output of quarto inspect and tries to figure out which input files Quarto needs and which output files Quarto will generate. It mostly works, but there are edge cases like ropensci/tarchetypes#102 and ropensci/tarchetypes#107 (mentioned in quarto-dev/quarto-r#14) (and it is not blazing fast either). On the other hand, tarchetypes::tar_quarto() is not in a position to circumvent quarto inspect and manually emulate the internal decisions and behaviors of Quarto. So it would be extremely helpful if Quarto would straightforwardly list all its input and output file paths for a project or document.