Spring-ai Support Ollama APIs for model management

• Extend the OllamaApi to support listing, copying, deleting, and pulling models programmatically.
• Improve setup for integration testing with Ollama and Testcontainers.

Enables gh-526

Comment From: ThomasVitale

Once this PR is merged, we should be able to remove the disabling logic from the Ollama integration tests since they are now all sharing the same Ollama container instance and re-using the same 3 (small) models across all tests (the only exception is the test in the Spring Boot Testcontainers module). It means the execution will be relatively fast, even on the GitHub Actions Runners.

Comment From: markpollack

alot of great cleanup, took 4 min to run on my machine. thanks.

Comment From: ThomasVitale

@markpollack thank you! I opened a followup PR to include the improvement suggested by @eddumelendez and because I forgot the test switch on, so the PR disables the integration tests again: https://github.com/spring-projects/spring-ai/pull/1538 Sorry about that!