HTML Report: Improve the way requests are related to their parent

[asfimport]

@pmouawad (Bug 65891): Currently HTML report generation works for CSV only and uses Naming policy to link a Transaction Controller with its children.

This may not be optimal at 2 levels:

• User must apply naming policy
• Doing that he loses sometimes the original information

Ideas to be enhanced:

• Add to CSV an information on hierarchy ?
• Recap in report the correspondance between Sampler Name and URL (rather specific to HTTP still)
• Other ideas ?

OS: All