Implement solution based merging for data collector

[MarcoRossignoli]

VSTest allows to post process artifacts, now we can implement solution wide report merge.

RFC https://github.com/microsoft/vstest-docs/blob/main/RFCs/0031-Test-Run-Attachments-Processing.md#how-to-register-an-idatacollectorattachmentprocessor

Contributes to #357

[EricStG]

Non-archived link (They merged into vstest): https://github.com/microsoft/vstest/blob/main/docs/RFCs/0031-Test-Run-Attachments-Processing.md

[github-actions]

This issue is stale because it has been open for 3 months with no activity.

[rcollette]

Relevant

[github-actions]

This issue is stale because it has been open for 3 months with no activity.

[rcollette]

Relevant

[github-actions]

This issue is stale because it has been open for 3 months with no activity.

[rcollette]

And still relevant