Semantic/rich logging

xUnit report files (XML) typically provide the relevant raw log output together with the errored, failed or skipped result. However, most verification frameworks, tools and methodologies do have more granular information about each entry. At least, the severity level is a built-in feature in VHDL, and several projects do provide additional logging utilities with further severity levels or failure reasons. For instance, VUnit supports custom logging levels, and can export rich logs to CSV files. Moreover, pyIPCMI includes vendor log processing features for classifying and optionally filtering the logs. Therefore, it would be interesting to support preserving the semantic information (at least the severity or specific vendor error/report code), in the extended xUnit report format used in OSVR. On top of that, librecores/eda-log-parser supports parsing logs from Verilator and Vivado, along with generating custom log entries to be used in CI systems/services, such as Azure or GitHub Actions.