Move global.push config to salt.auto_apply

The active-push tunables (enabled, highstate_interval_hours, debounce_seconds,
drain_interval, batch, batch_wait) described how Salt auto-applies changes, not
general grid config, so relocate them from the global namespace to a new
salt.auto_apply settings module.

- Add salt/salt/{defaults.yaml,auto_apply.map.jinja,soc_salt.yaml,adv_salt.yaml}.
  auto_apply.map.jinja is a dedicated, side-effect-free merge map (the existing
  salt/salt/map.jinja dereferences pillar.host.mainint at import time).
- Remove the push blocks from salt/global/{defaults,soc_global}.yaml.
- Register salt.soc_salt/salt.adv_salt in pillar/top.sls; seed the local pillar
  stubs for fresh installs (make_some_dirs) and upgrades (ensure_salt_local_pillar
  in soup, wired into up_to_3.2.0).
- Repoint all consumers: GLOBALMERGED.push.* -> AUTOAPPLY.* (schedule, salt
  master, manager beacons, beacons_pushstate, orch.push_batch) and
  pillar.get('global:push...') -> 'salt:auto_apply...' (push reactors,
  so-push-drainer).
- Add a salt: fleetwide-highstate entry to pillar_push_map.yaml so edits keep
  applying immediately, matching the prior global-namespace behavior.

salt/manager/files/beacons_pushstate.conf.jinja

@@ -1,7 +1,7 @@
-{% from 'global/map.jinja' import GLOBALMERGED %}
+{% from 'salt/auto_apply.map.jinja' import AUTOAPPLY %}
 beacons:
   pillar_db:
-    - interval: {{ GLOBALMERGED.push.drain_interval }}
+    - interval: {{ AUTOAPPLY.drain_interval }}
     - disable_during_state_run: True
   inotify:
     - disable_during_state_run: True