Add manual rake task to trigger automatic project registration

Implements https://gitlab.com/dependabot-gitlab/dependabot/-/issues/209

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Allure report

allure-report-publisher generated test report!

rspec: ✅ test report for a248d004

+----------------------------------------------------------+
|                    behaviors summary                     |
+-------------+--------+--------+---------+-------+--------+
|             | passed | failed | skipped | flaky | result |
+-------------+--------+--------+---------+-------+--------+
| jobs        | 14     | 0      | 0       | 0     | ✅     |
| services    | 165    | 0      | 0       | 0     | ✅     |
| models      | 3      | 0      | 0       | 0     | ✅     |
| controllers | 24     | 0      | 0       | 0     | ✅     |
| tasks       | 8      | 0      | 0       | 0     | ✅     |
| system      | 9      | 0      | 0       | 0     | ✅     |
+-------------+--------+--------+---------+-------+--------+
| Total       | 223    | 0      | 0       | 0     | ✅     |
+-------------+--------+--------+---------+-------+--------+