Add the "Table of contents"
When viewing "full" .md report in a browser rendered by GitHub or GitLab, it is possible to refer to particular part of the report -- for example, ..../e1_full_report.md#a001-system-information
will scoll down to the "A001 System information" section.
We need ToC in the very beginning of the full report, to allow easier navigation.
The open question – do we need ToC in individual .md reports? (For instance, to quickly jump to a particular replica's info)
Acceptance criteria
As a checkup report viewer, I can quickly navigate in the full .md report, switching between its parts quickly clicking on items in the Table of Contents.
Edited by Nikolay Samokhvalov