Better configuration (#79)

* Configurable Transport (#75)

* new functions to allow HTTPClient configuration

* updated go.mod for testing from remote

* updated go.mod for remote testing

* revert go.mod replace directives

* Fixed NewOrgClientWithTransport comment

* Make client fully configurable

* make empty messages limit configurable #70 #71

* make auth token private in config

* add docs

* lint

---------

Co-authored-by: Michael Fox <m.will.fox@gmail.com>

config.go

@@ -0,0 +1,33 @@
+package gogpt
+
+import (
+	"net/http"
+)
+
+const (
+	apiURLv1                       = "https://api.openai.com/v1"
+	defaultEmptyMessagesLimit uint = 300
+)
+
+// ClientConfig is a configuration of a client.
+type ClientConfig struct {
+	authToken string
+
+	HTTPClient *http.Client
+
+	BaseURL string
+	OrgID   string
+
+	EmptyMessagesLimit uint
+}
+
+func DefaultConfig(authToken string) ClientConfig {
+	return ClientConfig{
+		HTTPClient: &http.Client{},
+		BaseURL:    apiURLv1,
+		OrgID:      "",
+		authToken:  authToken,
+
+		EmptyMessagesLimit: defaultEmptyMessagesLimit,
+	}
+}