test: add rest catalog integration test

[HeartLinked]

Add integration testing infrastructure for the REST Catalog:

• Docker Compose setup (docker-compose.yml) for running a real REST catalog server
• Test utilities for process management (cmd_util.cc/h) - run cli commands
• Docker Compose control utilities (docker_compose_util.cc/h) - managing containerized services
• Created src/iceberg/test/util/ directory.
• Modified GitHub CI to support integration tests.
• These test cases(cmd / docker compose related)only work on Linux/MacOS, added conditional compilation flags for Linux-specific test utilities.

close #333 .

[wgtmac]

I just ran it on my MacOS and fall test cases failed.

[==========] Running 2 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 2 tests from RestCatalogIntegrationTest
[INFO] Starting to docker compose up, command: docker compose -p iceberg-rest-catalog-service up -d --wait --timeout 60
 Network iceberg-rest-catalog-service_rest_bridge  Creating
 Network iceberg-rest-catalog-service_rest_bridge  Created
 Container iceberg-rest-catalog-service-rest-1  Creating
 Container iceberg-rest-catalog-service-rest-1  Created
 Container iceberg-rest-catalog-service-rest-1  Starting
 Container iceberg-rest-catalog-service-rest-1  Started
 Container iceberg-rest-catalog-service-rest-1  Waiting
 Container iceberg-rest-catalog-service-rest-1  Healthy
[INFO] docker compose up succeed!
[INFO] Waiting for REST catalog to be ready at localhost:8181...
[INFO] REST catalog is ready!
[ RUN      ] RestCatalogIntegrationTest.MakeCatalogSuccess
/Users/gangwu/Projects/iceberg-cpp/src/iceberg/test/rest_catalog_test.cc:136: Failure
Value of: catalog_result
Expected: is an Ok result
  Actual: 40-byte object <0F-00 00-00 00-00 00-00 20-C0 74-03 00-60 00-00 1D-00 00-00 00-00 00-00 20-00 00-00 00-00 00-80 00-00 00-00 00-00 00-00>, which contains error: Failed to parse JSON string:

[  FAILED  ] RestCatalogIntegrationTest.MakeCatalogSuccess (53 ms)
[ RUN      ] RestCatalogIntegrationTest.ListNamespaces
/Users/gangwu/Projects/iceberg-cpp/src/iceberg/test/rest_catalog_test.cc:144: Failure
Value of: catalog_result
Expected: is an Ok result
  Actual: 40-byte object <0F-00 00-00 01-00 00-00 00-80 74-03 00-60 00-00 1D-00 00-00 00-00 00-00 20-00 00-00 00-00 00-80 00-C0 74-03 00-60 00-00>, which contains error: Failed to parse JSON string:

[  FAILED  ] RestCatalogIntegrationTest.ListNamespaces (34 ms)
[ DISABLED ] RestCatalogIntegrationTest.DISABLED_GetNonExistentNamespace
[ DISABLED ] RestCatalogIntegrationTest.DISABLED_CreateAndDropNamespace
[ DISABLED ] RestCatalogIntegrationTest.DISABLED_UpdateNamespaceProperties
[ DISABLED ] RestCatalogIntegrationTest.DISABLED_FullNamespaceWorkflow
[INFO] Starting to docker compose down, command: docker compose -p iceberg-rest-catalog-service down -v --remove-orphans
 Container iceberg-rest-catalog-service-rest-1  Stopping
 Container iceberg-rest-catalog-service-rest-1  Stopped
 Container iceberg-rest-catalog-service-rest-1  Removing
 Container iceberg-rest-catalog-service-rest-1  Removed
 Network iceberg-rest-catalog-service_rest_bridge  Removing
 Network iceberg-rest-catalog-service_rest_bridge  Removed
[INFO] docker compose down succeed!
[----------] 2 tests from RestCatalogIntegrationTest (87 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test suite ran. (4975 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 2 tests, listed below:
[  FAILED  ] RestCatalogIntegrationTest.MakeCatalogSuccess
[  FAILED  ] RestCatalogIntegrationTest.ListNamespaces