docs: comments in env sample (getting large!)

.env.sample

@@ -1,35 +1,43 @@
 TYPE=matrix-synapse
-
 DOMAIN=matrix.example.com
 LETS_ENCRYPT_ENV=production
+COMPOSE_FILE="compose.yml"
 
-SECRET_DB_PASSWORD_VERSION=v1
+## Admin details
 
 SYNAPSE_ADMIN_EMAIL=admin@example.com
 
-SECRET_REGISTRATION_SHARED_SECRET_VERSION=v1
-SECRET_MACAROON_SECRET_KEY_VERSION=v1
-SECRET_FORM_SECRET_VERSION=v1
+## Secrets
 
-COMPOSE_FILE="compose.yml"
+SECRET_DB_PASSWORD_VERSION=v1
+SECRET_FORM_SECRET_VERSION=v1
+SECRET_MACAROON_SECRET_KEY_VERSION=v1
+SECRET_REGISTRATION_SHARED_SECRET_VERSION=v1
+
+## Federation
 
 #DISABLE_FEDERATION=1
 
 # Set "true" to enable federation endpoint on $DOMAIN/.well-known/matrix/server
 SERVE_SERVER_WELLKNOWN=false
 
+## Registration
+
 ENABLE_REGISTRATION=false
 PASSWORD_LOGIN_ENABLED=true
 
+## Room auto-join
+
 #AUTO_JOIN_ROOM_ENABLED=1
 #AUTO_JOIN_ROOM="#example:example.com"
 
+## Logging
+
+# for the homserver
 SQL_LOG_LEVEL=WARN
 ROOT_LOG_LEVEL=WARN
 
-REDACTION_RETENTION_PERIOD=7d
-
-RETENTION_MAX_LIFETIME=4w
+## Privacy
 
 ENABLE_3PID_LOOKUP=true
 
@@ -37,14 +45,21 @@ USER_IPS_MAX_AGE=1d
 
 ENCRYPTED_BY_DEFAULT=all
 
-ALLOWED_LIFETIME_MAX=4w
-
 #ENABLE_ALLOWLIST=1
 #FEDERATION_ALLOWLIST="[]"
 
+## Retention
+
+ALLOWED_LIFETIME_MAX=4w
+
+REDACTION_RETENTION_PERIOD=7d
+RETENTION_MAX_LIFETIME=4w
+
 #MEDIA_RETENTION_LOCAL_LIFETIME=30d
 #MEDIA_RETENTION_REMOTE_LIFETIME=14d
 
+## Keycloak SSO
+
 #COMPOSE_FILE="$COMPOSE_FILE:compose.keycloak.yml"
 #KEYCLOAK_ENABLED=1
 #KEYCLOAK_ID=keycloak
@@ -55,12 +70,16 @@ ALLOWED_LIFETIME_MAX=4w
 #KEYCLOAK_ALLOW_EXISTING_USERS=false
 #SECRET_KEYCLOAK_CLIENT_SECRET_VERSION=v1
 
+## TURN
+
 #COMPOSE_FILE="$COMPOSE_FILE:compose.turn.yml"
 #TURN_ENABLED=1
 #TURN_URIS="[\"turns:coturn.foo.zone?transport=udp\", \"turns:coturn.foo.zone?transport=tcp\"]"
 #TURN_ALLOW_GUESTS=true
 #SECRET_TURN_SHARED_SECRET_VERSION=v1
 
+## SMTP
+
 #COMPOSE_FILE="$COMPOSE_FILE:compose.smtp.yml"
 #SMTP_ENABLED=1
 #SMTP_APP_NAME=
@@ -70,9 +89,13 @@ ALLOWED_LIFETIME_MAX=4w
 #SMTP_USER=
 #SECRET_SMTP_PASSWORD_VERSION=v1
 
+## App services
+
 #APP_SERVICES_ENABLED=1
 #APP_SERVICE_CONFIGS="[\"...\"]"
 
+## Telegram bridge
+
 #COMPOSE_FILE="$COMPOSE_FILE:compose.telegram.yml"
 #APP_SERVICE_BOT_USERNAME=telegrambot
 #APP_SERVICE_DISPLAY_NAME="Telegram bridge bot"
@@ -82,26 +105,32 @@ ALLOWED_LIFETIME_MAX=4w
 #VERIFY_SSL=false
 #ENABLE_ENCRYPTION=true
 #TELEGRAM_APP_ID=
-TELEGRAM_BRIDGE_PERMISSIONS="{ \"*\": \"relaybot\" }"
+#TELEGRAM_BRIDGE_PERMISSIONS="{ \"*\": \"relaybot\" }"
 #SECRET_TELEGRAM_DB_PASSWORD_VERSION=v1
 #SECRET_TELEGRAM_API_HASH_VERSION=v1
 #SECRET_TELEGRAM_BOT_TOKEN_VERSION=v1
 #SECRET_TELEGRAM_AS_TOKEN_VERSION=v1
 #SECRET_TELEGRAM_HS_TOKEN_VERSION=v1
 
+## Discord bridge
+
 #COMPOSE_FILE="$COMPOSE_FILE:compose.discord.yml"
 #DISCORD_CLIENT_ID=
 #DISCORD_BRIDGE_ADMIN=
 #SECRET_DISCORD_BOT_TOKEN_VERSION=v1
 #SECRET_DISCORD_DB_PASSWORD_VERSION=v1
 
+## Signal bridge
+
 #COMPOSE_FILE="$COMPOSE_FILE:compose.signal.yml"
 #SIGNAL_ENABLE_ENCRYPTION=true
-SIGNAL_BRIDGE_PERMISSIONS="{ \"*\": \"relay\" }"
+#SIGNAL_BRIDGE_PERMISSIONS="{ \"*\": \"relay\" }"
 #SECRET_SIGNAL_AS_TOKEN_VERSION=v1
 #SECRET_SIGNAL_DB_PASSWORD_VERSION=v1
 #SECRET_SIGNAL_HS_TOKEN_VERSION=v1
 
+## Shared auth
+
 #COMPOSE_FILE="$COMPOSE_FILE:compose.shared_secret_auth.yml"
 #SHARED_SECRET_AUTH_ENABLED=1
 #SECRET_SHARED_SECRET_AUTH_VERSION=v1 # length=128