feat: add seekdb which is lite version of oceanbase (#12692)

### What problem does this PR solve?

Add seekdb as doc_engine wich is the lite version of oceanbase.
close #12691
### Type of change

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

docker/.env

@@ -16,6 +16,7 @@
 # - `infinity` (https://github.com/infiniflow/infinity)
 # - `oceanbase` (https://github.com/oceanbase/oceanbase)
 # - `opensearch` (https://github.com/opensearch-project/OpenSearch)
+# - `seekdb` (https://github.com/oceanbase/seekdb)
 DOC_ENGINE=${DOC_ENGINE:-elasticsearch}
 
 # Device on which deepdoc inference run.
@@ -92,6 +93,19 @@ OB_SYSTEM_MEMORY=${OB_SYSTEM_MEMORY:-2G}
 OB_DATAFILE_SIZE=${OB_DATAFILE_SIZE:-20G}
 OB_LOG_DISK_SIZE=${OB_LOG_DISK_SIZE:-20G}
 
+# The hostname where the SeekDB service is exposed
+SEEKDB_HOST=seekdb
+# The port used to expose the SeekDB service
+SEEKDB_PORT=2881
+# The username for SeekDB
+SEEKDB_USER=root
+# The password for SeekDB
+SEEKDB_PASSWORD=infini_rag_flow
+# The doc database of the SeekDB service to use
+SEEKDB_DOC_DBNAME=ragflow_doc
+# SeekDB memory limit
+SEEKDB_MEMORY_LIMIT=2G
+
 # The password for MySQL.
 # WARNING: Change this for production!
 MYSQL_PASSWORD=infini_rag_flow