* refactor: Move http client into provider
* refactor: Rework ollama provider for work with internal http client
* refactor: Rework LM Studio provider to work with internal http client
* refactor: Rework Mistral AI to work with internal http client
* fix: Replace url and header to QNetworkRequest
* refactor: Rework Google provider to use internal http client
* refactor: OpenAI compatible providers switch to use internal http client
* fix: Remove m_requestHandler from tests
* refactor: Remove old handleData method
* fix: Remove LLMClientInterfaceTest