docs: installation (#3646)

* improve compose

* docs: installation v2

* ZITADEL_EXTERNALSECURE=true is sane

* Update docs/docs/guides/installation/configuration.mdx

* docs: download binaries from command line

* docs: better config description

* fixes

* default instance

* default user credentials

Co-authored-by: Livio Amstutz <livio.a@gmail.com>

deploy/compose/docker-compose.yaml

@@ -0,0 +1,46 @@
+version: '3.8'
+
+services:
+  zitadel:
+    restart: always
+    networks:
+      - zitadel
+    image: ghcr.io/zitadel/zitadel:v1.80.0-v2.20-amd64
+    command: admin start-from-init --masterkeyFromEnv
+    environment:
+      - ZITADEL_MASTERKEY=${ZITADEL_MASTERKEY}
+      - ZITADEL_DATABASE_HOST=db
+      - ZITADEL_EXTERNALSECURE=false
+      # TODO: Use the following variables as defaults
+      - ZITADEL_EXTERNALDOMAIN=localhost
+      - ZITADEL_S3DEFAULTINSTANCE_CUSTOMDOMAIN=localhost
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8080/debug"]
+      interval: 10s
+      timeout: 30s
+      retries: 5
+      start_period: 40s
+    depends_on:
+      db:
+        condition: service_healthy
+    ports:
+      - 8080:8080
+
+  db:
+    restart: always
+    networks:
+      - zitadel
+    image: cockroachdb/cockroach:v21.2.8
+    command: start-single-node --insecure --listen-addr=0.0.0.0
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8080/health?ready=1"]
+      interval: 10s
+      timeout: 30s
+      retries: 5
+      start_period: 20s
+    ports:
+      - 9090:8080
+      - 26257:26257
+
+networks:
+  zitadel: