Mastodon: allow internal chess host & refactor var names; OpenLDAP: safer get_app_conf

- Add ALLOWED_PRIVATE_ADDRESSES to .env (from svc-db-postgres) to handle 422 Mastodon::PrivateNetworkAddressError
- Switch docker-compose to MASTODON_* variables and align vars/main.yml
- Always run 01_setup.yml during deployment (removed conditional flag)
- OpenLDAP: remove implicit True default on network.local to avoid unintended truthy behavior

Context: chess.infinito.nexus resolved to 192.168.200.30 (private IP) from Mastodon; targeted allowlist unblocks federation lookups.

Ref: https://chat.openai.com/share/REPLACE_WITH_THIS_CONVERSATION_LINK

roles/web-app-mastodon/config/main.yml

@@ -1,5 +1,4 @@
 single_user_mode:     false                                           # Set true for initial setup
-setup:                true                                            # Set true in inventory file to execute the setup and initializing procedures, don't know if this is still necessary @todo test it                        
 features:
   matomo:             true
   css:                true