The demo code isn’t ‘complete’ wrt to an exhaustive set of drivers. With the data sheet and UG for the STM32F103 you should be able to ‘clone’ the DMA1 driver to make the DMA2 driver.
Some exercises are left to the student to complete.
Just to extend what John W says - the libraries are provided by ST themselves, and they will have a complete set of the the latest versions on their website. The drivers in the FreeRTOS distribution will be older, and probably only include the files used by the demo.