Dynamically create the service_conf.yaml file by replacing environment variables from .env (#3341)

### What problem does this PR solve?

This pull request implements the feature mentioned in #3322. 

Instead of manually having to edit the `service_conf.yaml` file when
changes have been made to `.env` and mapping it into the docker
container at runtime, a template file is used and the values replaced by
the environment variables from the `.env` file when the container is
started.
 

### Type of change

- [X] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
Co-authored-by: Zhichang Yu <yuzhichang@gmail.com>

docker/service_conf.yaml.template

@@ -0,0 +1,74 @@
+ragflow:
+  host: ${RAGFLOW_HOST:-0.0.0.0}
+  http_port: 9380
+mysql:
+  name: '${MYSQL_DBNAME:-rag_flow}'
+  user: '${MYSQL_USER:-root}'
+  password: '${MYSQL_PASSWORD:-infini_rag_flow}'
+  host: '${MYSQL_HOST:-mysql}'
+  port: 3306
+  max_connections: 100
+  stale_timeout: 30
+minio:
+  user: '${MINIO_USER:-rag_flow}'
+  password: '${MINIO_PASSWORD:-infini_rag_flow}'
+  host: '${MINIO_HOST:-minio}:9000'
+es:
+  hosts: 'http://${ES_HOST:-es01}:9200'
+  username: '${ES_USER:-elastic}'
+  password: '${ES_PASSWORD:-infini_rag_flow}'
+redis:
+  db: 1
+  password: '${REDIS_PASSWORD:-infini_rag_flow}' 
+  host: '${REDIS_HOST:-redis}:6379'
+
+# postgres:
+#   name: '${POSTGRES_DBNAME:-rag_flow}'
+#   user: '${POSTGRES_USER:-rag_flow}'
+#   password: '${POSTGRES_PASSWORD:-infini_rag_flow}'
+#   host: '${POSTGRES_HOST:-postgres}'
+#   port: 5432
+#   max_connections: 100
+#   stale_timeout: 30
+# s3:
+#   endpoint: 'endpoint'
+#   access_key: 'access_key'
+#   secret_key: 'secret_key'
+#   region: 'region'
+# azure:
+#   auth_type: 'sas'
+#   container_url: 'container_url'
+#   sas_token: 'sas_token'
+# azure:
+#   auth_type: 'spn'
+#   account_url: 'account_url'
+#   client_id: 'client_id'
+#   secret: 'secret'
+#   tenant_id: 'tenant_id'
+#   container_name: 'container_name'
+# user_default_llm:
+#   factory: 'Tongyi-Qianwen'
+#   api_key: 'sk-xxxxxxxxxxxxx'
+#   base_url: ''
+# oauth:
+#   github:
+#     client_id: xxxxxxxxxxxxxxxxxxxxxxxxx
+#     secret_key: xxxxxxxxxxxxxxxxxxxxxxxxxxxx
+#     url: https://github.com/login/oauth/access_token
+#   feishu:
+#     app_id: cli_xxxxxxxxxxxxxxxxxxx
+#     app_secret: xxxxxxxxxxxxxxxxxxxxxxxxxxxx
+#     app_access_token_url: https://open.feishu.cn/open-apis/auth/v3/app_access_token/internal
+#     user_access_token_url: https://open.feishu.cn/open-apis/authen/v1/oidc/access_token
+#     grant_type: 'authorization_code'
+# authentication:
+#   client:
+#     switch: false
+#     http_app_key:
+#     http_secret_key:
+#   site:
+#     switch: false
+# permission:
+#   switch: false
+#   component: false
+#   dataset: false