[#8891] feat(lance-rest-server): Add standalone and auxiliary mode support for Lance REST service

[youngyjd]

What changes were proposed in this pull request?

1. Created service discovery file (META-INF/services/org.apache.gravitino.auxiliary.GravitinoAuxiliaryService)
2. Added unit tests (TestLanceConfig.java)

Why are the changes needed?

Fix: #8891

To enable flexible deployment of Lance REST service:

Standalone mode (independent JVM):

• Lance needs to connect to Gravitino server via HTTP to access catalog/schema/table metadata
• GRAVITINO_URI and GRAVITINO_METALAKE configs specify the connection parameters
• Use case: Deploy Lance REST separately for isolation or scaling

Auxiliary mode (embedded in Gravitino server):

• Lance runs in the same JVM as Gravitino, enabling direct memory access (zero overhead)
• META-INF/services file enables automatic service discovery via Java ServiceLoader
• Use case: Simplified deployment with shared resources and unified monitoring

Does this PR introduce any user-facing change?

Yes - New configuration properties

For Standalone Mode:

# Required: Gravitino server URI
gravitino.lance-rest.gravitino-uri=http://gravitino-server:8090

# Required: Metalake name
gravitino.lance-rest.gravitino-metalake=production

For Auxiliary Mode:

# Enable Lance REST as auxiliary service
gravitino.auxService.names=iceberg-rest,lance-rest

# Classpath for Lance REST JAR
gravitino.lance-rest.classpath=lance/lance-rest-server/build/libs

Deployment modes supported:
Standalone: Lance REST runs independently, connects to Gravitino via HTTP
Auxiliary: Lance REST runs embedded in Gravitino, uses direct memory access
No breaking changes - all changes are additive and backward compatible.

How was this patch tested?

1. unit test
2. manual test

Standalone mode test:

junda@java(junda.devpod-us-or) ~/gravitino/distribution/package/bin
 % ./gravitino.sh start
Gravitino Server is running[PID:3907790]
junda@java(junda.devpod-us-or) ~
 % curl http://localhost:8090/api/version
{"code":0,"version":{"version":"1.1.0-SNAPSHOT","compileDate":"23/10/2025 21:03:17","gitCommit":"35bd819975badea2493b4dbd9d0de68425229945"}}%   

junda@java(junda.devpod-us-or) ~/gravitino/distribution/package/bin
 % ./gravitino-lance-rest-server.sh start
GravitinoLanceRESTServer is running[PID:3930096]
junda@java(junda.devpod-us-or) ~
 % curl "http://localhost:9101/lance/v1/namespace/root/list"
{"id":"root","delimiter":"$","namespaces":["default"]}%   

Auxiliary mode test:

junda@java(junda.devpod-us-or) ~/gravitino/distribution/package
 % cd /home/user/gravitino && cat >> distribution/package/conf/gravitino.conf << 'EOF'

# ===== Lance REST Auxiliary Service =====
gravitino.auxService.names = iceberg-rest,lance-rest
gravitino.lance-rest.classpath = /home/user/gravitino/lance/lance-rest-server/build/libs
gravitino.lance-rest.catalog-name = lance_catalog
EOF

junda@java(junda.devpod-us-or) ~/gravitino/distribution/package
 % ./bin/gravitino.sh start          
Gravitino Server is running[PID:274396]

junda@java(junda.devpod-us-or) ~/gravitino/distribution/package
 % tail -50 logs/gravitino-server.log | grep -i lance | grep -i started
2025-10-23 21:34:41.495 INFO [main] [org.apache.gravitino.server.web.JettyServer.start(JettyServer.java:202)] - lance-rest web server started on host 0.0.0.0 port 9101.
2025-10-23 21:34:41.495 INFO [main] [org.apache.gravitino.lance.LanceRESTService.serviceStart(LanceRESTService.java:77)] - Lance REST service started

[mchades]

LGTM. Could you plz resolve the conflicts? thx

[mchades]

lgtm.