Add support for fully offline binary via compile-time 'offline' tag (#272)

* Add support for fully offline binary via compile-time 'offline' tag

* Update docs

client/lib/net_disabled.go

@@ -0,0 +1,14 @@
+//go:build offline
+// +build offline
+
+package lib
+
+import "net/http"
+
+func GetHttpClient() *http.Client {
+	panic("Cannot GetHttpClient() from a hishtory client compiled with the offline tag!")
+}
+
+func IsOfflineBinary() bool {
+	return true
+}