"Lock/Unlock all" button for regions

**Is your feature request related to a problem? Please describe.**
There is no feature that allows me to lock all regions. I have the object ground truth for my data already. I do not want to touch the position of any bbox in my image. I just want to create relations and grouping between them.

**Describe the solution you'd like**
Just like there is a "hide/unhide all" button. It would be good to have a "lock/unlock all" button for regions.