Make docker compose less dependent on .env file

dev/docker-compose.yml

@@ -1,5 +1,3 @@
-version: "3.9"
-
 services:
   mssql:
     image: mcr.microsoft.com/mssql/server:2022-latest
@@ -34,7 +32,7 @@ services:
   mail:
     image: sj26/mailcatcher:latest
     ports:
-      - "${MAILCATCHER_PORT}:1080"
+      - "${MAILCATCHER_PORT:-1080}:1080"
       - "10250:1025"
     profiles:
       - mail
@@ -76,8 +74,8 @@ services:
     ports:
       - "8090:8080"
     environment:
-      SIMPLESAMLPHP_SP_ENTITY_ID: ${IDP_SP_ENTITY_ID}
-      SIMPLESAMLPHP_SP_ASSERTION_CONSUMER_SERVICE: ${IDP_SP_ACS_URL}
+      SIMPLESAMLPHP_SP_ENTITY_ID: ${IDP_SP_ENTITY_ID:-http://localhost:51822/saml}
+      SIMPLESAMLPHP_SP_ASSERTION_CONSUMER_SERVICE: ${IDP_SP_ACS_URL:?error}
       SIMPLESAMLPHP_SP_SINGLE_LOGOUT_SERVICE: null
     volumes:
       - ./authsources.php:/var/www/simplesamlphp/config/authsources.php
@@ -104,8 +102,8 @@ services:
     volumes:
       - "./reverse-proxy.conf:/etc/nginx/conf.d/default.conf"
     ports:
-      - "${API_PROXY_PORT}:${API_PROXY_PORT}"
-      - "${IDENTITY_PROXY_PORT}:${IDENTITY_PROXY_PORT}"
+      - "${API_PROXY_PORT:-4100}:${API_PROXY_PORT:-4100}"
+      - "${IDENTITY_PROXY_PORT:-33756}:${IDENTITY_PROXY_PORT:-33756}"
     profiles:
       - proxy