copy over FsrUtils package from 21.2
Given how far 21.2 and master have diverged for this package I decided that I'd rather copy over the entire package from 21.2 and fix any issues encountered instead of trying to do a cherry-pick or other "smart" merge. If any independent development happened in master it will be wiped out by this MR.
Marking this as draft until !43285 (merged) gets merged, as these changes require the AsgToolConfig::makePrivateTool()
method.
cc @schaffer