Create scheduled report of failed review app deployments to slack

There is a script in toolbox to list recent failed review app deployments. We should run this at regular intervals and post it to slack for easy access to debug and identify causes for failures.

Example:

 bundle exec bin/failed_review_app_deploys_report --hours 12
+--------------+-----------------+--------------------------------+--------------+--------------------------------------------------------------+
|      id      |       name      |           created_at           |    status    |                            web_url                           |
+--------------+-----------------+--------------------------------+--------------+--------------------------------------------------------------+
|    486018621 | review-deploy   | 2020-03-26T02:08:11.807Z       | failed       | https://gitlab.com/gitlab-org/gitlab/-/jobs/486018621        |
|    486003157 | review-deploy   | 2020-03-26T01:37:13.343Z       | failed       | https://gitlab.com/gitlab-org/gitlab/-/jobs/486003157        |
|    485897198 | review-deploy   | 2020-03-25T22:35:33.849Z       | failed       | https://gitlab.com/gitlab-org/gitlab/-/jobs/485897198        |
|    485708061 | review-deploy   | 2020-03-25T19:13:34.408Z       | failed       | https://gitlab.com/gitlab-org/gitlab/-/jobs/485708061        |
|    485651543 | review-deploy   | 2020-03-25T18:25:23.082Z       | failed       | https://gitlab.com/gitlab-org/gitlab/-/jobs/485651543        |
+--------------+-----------------+--------------------------------+--------------+--------------------------------------------------------------+