Issue Summary

According to How dashboards, boards and filters are migrated, using the "All dashboards" option should include "all dashboards on your server or Data Center." however this does not include the System Dashboard. This should also include the Introduction gadget.

Steps to Reproduce

1. Create a new migration and include the "All dashboards" option
2. Run the migration

Expected Results

The system dashboard is migrated

Actual Results

The System Dashboard is ignored

Workaround

Reconfigure the System Dashboard manually

Suggestion

Provide a checkbox option to include/overwrite the System Dashboard.