* refactoring http request creation and sending
* fix lint error
* increase the test coverage of client.go
* refactor: Change the style of HTTPRequestBuilder.Build func to one-argument-per-line.
* chore(config.go): update Azure API version to 2023-05-15 to use the latest version available
* chore(api_internal_test.go): update Azure API version to 2023-05-15 to match the latest version
* feat: add azure openai support
* chore: refine config
* chore: make config options like the python one
* chore: adjust config struct field order
* test: fix tests
* style: make the linter happy
* fix: support Azure API Key authentication in sendRequest
* chore: check error in CreateChatCompletionStream
* chore: pass tests
* chore: try pass tests again
* chore: change ClientConfig back due to this lib does not like WithXxx config style
* chore: revert fix to CreateChatCompletionStream() due to cause tests not pass
* chore: at least add some comment about the required fields
* chore: re order ClientConfig fields
* chore: add DefaultAzure()
* chore: set default api_version the same as py one "2023-03-15-preview"
* style: fixup typo
* test: add api_internal_test.go
* style: make lint happy
* chore: add constant AzureAPIKeyHeader
* chore: use AzureAPIKeyHeader for api-key header, fix azure base url auto trim suffix /
* test: add TestAzureFullURL, TestRequestAuthHeader and TestOpenAIFullURL
* test: simplify TestRequestAuthHeader
* test: refine TestOpenAIFullURL
* chore: refine comments
* feat: DefaultAzureConfig
