Block backfilling (#12968)

* backfill service

* fix bug where origin state is never unlocked

* support mvslice states

* use renamed interface

* refactor db code to skip block cache for backfill

* lint

* add test for verifier.verify

* enable service in service init test

* cancellation cleanup

* adding nil checks to configset juggling

* assume blocks are available by default

As long as we're sure the AvailableBlocker is initialized correctly
during node startup, defaulting to assuming we aren't in a checkpoint
sync simplifies things greatly for tests.

* block saving path refactor and bugfix

* fix fillback test

* fix BackfillStatus init tests

---------

Co-authored-by: Kasey Kirkham <kasey@users.noreply.github.com>

hack/update-go-pbs.sh

@@ -18,8 +18,8 @@ searchstring="prysmaticlabs/prysm/v4/"
 for ((i = 0; i < arraylength; i++)); do
     color "34" "$destination"
     destination=${file_list[i]#*$searchstring}
-    chmod 755 "$destination"
     cp -R -L "${file_list[i]}" "$destination"
+    chmod 755 "$destination"
 done
 
 # Run goimports on newly generated protos