Automatically check Markdown files with SonarSource

[Philipp Salvisberg]

Starting with version 4.3 of the db* CODECOP CLI it's possible to analyze Markdown files. In fact only the SQL code blocks will be analyzed (similar to the formatter). Furthermore this version produces by default also a Generic Issue Import Format.

This allows to set-up an fully-automated check of all Markdown files in this repository and publish the results to SonarCloud using GitHub actions. The configuration should cover all branches.

This way syntax errors and unwanted violations of own rules can be discovered faster.

The wanted violations should be marked as false positives.