storcon: make pageserver AZ id mandatory (#8856)

## Problem
https://github.com/neondatabase/neon/pull/8852 introduced a new nullable
column for the `nodes` table: `availability_zone_id`

## Summary of changes
* Make neon local and the test suite always provide an az id
* Make the az id field in the ps registration request mandatory
* Migrate the column to non-nullable and adjust in memory state
accordingly
* Remove the code that was used to populate the az id for pre-existing
nodes

test_runner/fixtures/neon_fixtures.py

@@ -758,6 +758,9 @@ class NeonEnvBuilder:
         patch_script = ""
         for ps in self.env.pageservers:
             patch_script += f"UPDATE nodes SET listen_http_port={ps.service_port.http}, listen_pg_port={ps.service_port.pg}  WHERE node_id = '{ps.id}';"
+            # This is a temporary to get the backward compat test happy
+            # since the compat snapshot was generated with an older version of neon local
+            patch_script += f"UPDATE nodes SET availability_zone_id='{ps.az_id}'  WHERE node_id = '{ps.id}' AND availability_zone_id IS NULL;"
         patch_script_path.write_text(patch_script)
 
         # Update the config with info about tenants and timelines