Developer changelog handling

Included in this release:

• Driver: Added missing implementation for the areaExists().
• Driver: Made the use of the dev-changelog.md file official.
• Driver: Added the helper class DevChangelog to parse the developer changelog file.
• Driver: The version file can now optionally be automatically generated.

Update guide

To make use of the new version file generation mechanism, use the following code
for the driver's getExtendedVersion() method:

public function getExtendedVersion() : string
{
    return AppFactory::createDevChangelog()->getCurrentVersion()->getTagVersion();
}