[Report][Added] Expand relative paths to specific outputs

[nguyen-v]

This PR adds to the report output a new expansion pattern ${<output_name>_outpath_<index>} (index optional, starts at 1), which returns the relative path between the generated report file and the output. This is useful for creating README files or other files that need a relative path to a specific file.

Example configuration:
https://github.com/nguyen-v/KiBot/blob/report_out_path/tests/yaml_samples/report_output_path.kibot.yaml

With this template:
https://github.com/nguyen-v/KiBot/blob/report_out_path/tests/data/report_output_path.txt

Generates:
https://github.com/nguyen-v/KiBot/blob/report_out_path/tests/reference/5_1_7/light_control-report_output_path_1.txt
https://github.com/nguyen-v/KiBot/blob/report_out_path/tests/reference/5_1_7/light_control-report_output_path_2.txt

[set-soft]

Please use symlinks for the reference files, they are all the same, so keep one and link the others.