Introduce a 'reports' directory

[cmacq2]

Introduce a 'reports' directory to aggregate reports generated via custom-report.sh

With this change custom-report.sh instances will have a well-defined location to put their reports (example: $(br_report_dir)/your_report_name_here.txt), and brickstrap has a well-defined location to delete, namely $(br_report_dir) itself.

Introduce the br_output_basename function so reporting scripts have a well defined template basename for report file names.

[cmacq2]

Any thoughts on this?

[dlech]

Looks good to me. I might be inclined to call the br_output_basename function br_image_basename instead.

[cmacq2]

I thought of that but decided against it when I wrote the code because:

• It is intended for use by scripts such as custom-report.sh for filenames of arbitrary output artifacts
• There's also brp_image_name which reflects the actual image base name. It seemed a good idea to preserve the distinction/avoid confusion in the function name.

[dlech]

Isn't brp_image_name the full name (including file extension)? Also, since the "output" name can be specified with the -I option (advertised as image base name), I think it makes more sense to use br_image_basename unless you are planning on making it more generic by updating the docs and maybe changing the parameter to -o.

[cmacq2]

Isn't brp_image_name the full name (including file extension)?

Correct.

I think it makes more sense to use br_image_basename

Updated the PR accordingly.