github page improvements

[dorin100]

• do we still need the "Publishing testing results" section on the Readme of the cardano-node-tests? --> remove the section
• can we see the historic results of the nightly pipelines?
• create a template for the Tag Testing page
• create Issue, FR, PR templates
• the links for the "Sync testing ..." + "DB revalidation testing ..." should point to the github page
• explain all the statuses in the allure reports (skipped, expected failed, failed, etc)
• open all the test reports on a different page
• for the nightly test results it would be best if we would also see:
  • cardano-node version, cardano-node-tests version, db-sync version
  • the html report for simpler debugging
  • environment name (local cluster, preview, preprod, etc)
  • specific parameters (p2p, utxo-hd, cddl)
• documentation for "how to interact with an existing environment using cardano-node-test"
• add a section for "help needed" (in case somebody from the community wants to help)
• add link to "cardano environments" page
• add a link to "Grafana Dashboards" for monitoring existing public environments
• explain the system tests coverage and approach (property + feature e2e tests (positive and negative, functional and non-functional))