GSK feedback - important vs 'appendix' type information to improve readibility

Currently the report is very verbose, and not human friendly. Feedback received ([in this meeting](https://github.com/insightsengineering/thevalidatoR/discussions/43)) to try and split it out - e.g. can we target something like 1 page that flags key issues, and push back things like the record of how each documented feature was tested to an appendix.

Tagging people that attended: @dgkf @epijim @tlblnk

An example report run on `admiral` with current template is attached.

[validation-report.pdf](https://github.com/insightsengineering/thevalidatoR/files/7996951/validation-report.pdf)