Shard out disabling running during firstboot (provisioning)

Summary:
- Let's defer setting up systemd timers till after workload.ready on boxes
  - These should not be needed for provisioning a new box ready for workload
- If there are, we should fix (e.g. explicitly run the timers .service file or command from chef)
  - Use not_if to shard out and eventually gate all of our infra out of first boot setup of systemd timers
  - Good for OSS people to do too ...

Differential Revision: D59290162

fbshipit-source-id: 52168797949fb4fae5330d301c1b9deb5a0116b4

cookbooks/fb_timers/recipes/default.rb

@@ -58,4 +58,6 @@
   group node.root_group
 end
 
-fb_timers_setup 'fb_timers system setup'
+fb_timers_setup 'fb_timers system setup' do
+  not_if { (node.firstboot_os? || node.firstboot_tier?) && node.in_shard?(0) } # __BUMP__
+end