[build] don't require passwordless sudo #11417

Why I did it
Not all build environments have passwordless sudo enabled for all users

How I did it
Instead of using sudo to delete fsroot directories, mount them in a small, temporary docker container and delete them from there

How to verify it
Build in an environment where the build user does not have passwordless sudo enabled and confirm that no sudo password prompts are seen

Makefile.work

@@ -202,7 +202,8 @@ endif
 DOCKER_LOCKFILE_SAVE := $(DOCKER_LOCKDIR)/docker_save.lock
 $(shell mkdir -m 0777 -p $(DOCKER_LOCKDIR))
 $(shell [ -f $(DOCKER_LOCKFILE_SAVE) ] || (touch $(DOCKER_LOCKFILE_SAVE) && chmod 0777 $(DOCKER_LOCKFILE_SAVE)))
-$(shell sudo rm -rf $(DOCKER_ROOT) && mkdir -p $(DOCKER_ROOT))
+$(docker run --rm -v $(DOCKER_ROOT)\:/mount alpine sh -c 'rm -rf /mount/')
+$(mkdir -p $(DOCKER_ROOT))
 
 ifeq ($(DOCKER_BUILDER_MOUNT),)
 override DOCKER_BUILDER_MOUNT := "$(PWD):/sonic"