[DevOps Adoption] Add an adoption table in the Overview tab

Overview

With #330401 (closed) we now have an Overview tab in DevOps Adoption but there are a couple of issues with how the table is being displayed.

Problems to solve

1. The "Add sub-group to table" selector is displayed in the Overview tab even though there is no table on that page.

   

2. If I can't see the list of groups in the Overview tab, I can't easily see which groups are being considered in the adoption progress bar.

3. The "Add sub-group to table" selector is displayed in each of the Dev, Sec, and Ops tabs. Adding a sub group to the table in one tab adds it to the table in all tabs. This might not be intuitive with the current design.

Proposal

1. Include a table in the Overview page so that users can easily see which groups are being considered for the progress bar data
2. The table on the Overview page looks like
3. The table has the delete icon in each row

Requirements

1. The "Add or remove subgroup" selector works to add or remove groups from the table in the Overview tab.
2. When subgroups are added or removed from the Overview tab, they are also added/removed from the Dev, Sec, and Ops tabs