Generator: simply overwrite axios baseurl

The axios baseURL is the target of any api request. To set it you currently have to do something like this:

const client = new ShareSecretApiClient();
client.axios.defaults.baseURL = "https://api.domain.tld";

Thats not simple or even intuitive.

Proposed Solution

To make this more user-friendly, we could introduce an option to set the baseURL directly in the ApiClient constructor. This way, users can easily configure the baseURL when creating an instance of the client. Here's an example of how this might look:

const client = new ShareSecretApiClient({ baseURL: "https://api.domain.tld" });

Start at the generated ApiClient constructor and the current axios.defaults.baseURL assignment. Trace how constructor options reach the client, then verify that passing baseURL when creating ShareSecretApiClient changes the target used by API requests.