Support deterministic paths

[mawosoft]

Scenarios

• User-provided mapping via arguments/settings
• Reuse existing mappings from ReportGenerator and/or Coverlet?
• Find the (git) repo root based on the current directory. Should be fairly successful despite a few edge cases.
  • There can be more than one repo (submodules).
  • Even within a project/solution tree, there can still be references to files outside that tree.
  • What if it's not git?
  • An alternative/additional way to current directory could be directory from report file inputs?