Set DAST_SPIDER_START_AT_HOST default to false

Context

#258805 (closed) introduced the DAST_SPIDER_START_AT_HOST variable, allowing the user to decide if they want the DAST scan to start at the target or the target's host.

The default was set to true to preserve the existing functionality. In %14.0, we want to switch it to false.

Solution

Use config.dast_major_version to switch the DAST_SPIDER_START_AT_HOST to default to False when config.dast_major_version >= 2