clear stale docker network endpoints before starting containers

docker_container.running fails with an address-already-in-use error when a
container holds a stale sobridge endpoint - either after its IP changes in
pillar or after an unclean shutdown leaves the endpoint behind.

Add the clear_stale_endpoint macro and call it from every enabled.sls whose
container attaches to sobridge with a static IP. The macro force-disconnects
the container from the network only when its current endpoint IP does not
match the one salt is about to assign, so it is a no-op on a normal highstate.

The strelka states use state IDs that differ from their container names, so
those calls pass state_id explicitly. nginx resolves its IP through
container_config, which varies by role.

salt/postgres/enabled.sls

@@ -8,6 +8,9 @@
 {%   from 'vars/globals.map.jinja' import GLOBALS %}
 {%   from 'docker/docker.map.jinja' import DOCKERMERGED %}
 {%   set SO_POSTGRES_USER = salt['pillar.get']('postgres:auth:users:so_postgres_user:user', 'so_postgres') %}
+{%   from 'docker/macros/docker_endpoint.jinja' import clear_stale_endpoint %}
+
+{{ clear_stale_endpoint('so-postgres', 'sobridge', DOCKERMERGED.containers['so-postgres'].ip) }}
 
 include:
   - postgres.auth