Add GetObjectDirectorySize RPC

This RPC will be used to determine if a push will
exceed the size limit of a repository.
4 jobs for pb-get-object-directory-size-1-22 in 1 minute and 54 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #238426056
build

00:01:53

passed #238426057
check-grpc-proto-clients

00:01:50

passed #238426058
danger-review

00:00:53

passed #238426055
test

00:01:48