Go: implement provider: Ollama (#14580)

### What problem does this PR solve?

implement `Ollama` provider

### Type of change

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

---------

Co-authored-by: Jin Hai <haijin.chn@gmail.com>

conf/models/ollama.json

@@ -0,0 +1,8 @@
+{
+  "name": "ollama",
+  "url_suffix": {
+    "chat": "chat/completions",
+    "models": "models"
+  },
+  "class": "local"
+}