add ability to create a client without env file

[Tyrell04]

If you use Ollama as a Go package, you are forced to use an environment variable as a configuration to change the host. With the CreateClient function, you are free to use your own configuration passed into the Ollama client.

[pdevine]

Hey @Tyrell04 thanks for submitting the PR, but you can already do this w/ NewClient() in client.go. I'm going to go ahead and close the PR.

[Tyrell04]

How could I implement an alternative method to create a client that is not using an env variable? The Problem with the given implementation is that I am forced to use env as config for my project.

[pdevine]

@Tyrell04 you just call api.NewClient(). The function header looks like: NewClient(base *url.URL, http *http.Client), so just pass it a url.URL object and an http client.