prebuilt usvfs was missing sources

upgrade pip to avoid warnings
copy openssl dlls to prebuilt python so pip can connect through https
pyqt needs to copy qt dlls in prebuilt too

src/tasks/python.cpp

@@ -100,6 +100,12 @@ void python::fetch_prebuilt()
 
 void python::build_and_install_prebuilt()
 {
+	op::copy_glob_to_dir_if_better(cx(),
+		openssl::bin_path() / "*.dll",
+		python::build_path(),
+		op::copy_files);
+
+	install_pip();
 	copy_files();
 }
 
@@ -202,6 +208,12 @@ void python::install_pip()
 	run_tool(process_runner(process()
 		.binary(python_exe())
 		.arg("-m", "ensurepip")));
+
+	run_tool(process_runner(process()
+		.binary(python_exe())
+		.arg("-m pip")
+		.arg("install")
+		.arg("--upgrade pip")));
 }
 
 fs::path python::python_exe()