Missing several libraries when building Tofino backend

[XiangyuG]

I find several libraries are missing when installing the tofino backend. For example, I use machine with ubuntu 20.04 and have to install the following libraries: (1) sudo apt install rapidjson-dev (2) pip3 install jsl pyinstaller jsonschema

[fruffy]

We should add this to the documentation. @pkotikal @hanw Do you know who is responsible for maintaining the Tofino back end at this point?

[hanw]

@psivanup should be able to help with issue on tofino backend.