increase build cache hit to reduce the build time.

[1mujue]

Feature: Change the structure of Dockerfile and requirements.txt to make rbnx build (which will use docker build) have more docker layer cache hit and make it easier to use HTTP_PROXY. The change will be shown later.

1. How to use proxy easier? Look at this example:
   RUN without-proxy python3 -m pip install(NOT use proxy)
   RUN with-build-proxy python3 -m pip install(use proxy)
2. To supervise the install progress of pip, add --progress-bar raw.
3. The requirements.txt(it is reserved) has been spilt into 4 parts: scene-base.txt, scene-perception-core.txt, scene-perception-heavy.txt, scene-pytorch3d.txt. All of them are in requirements DIRECTORY. Use four RUN pip install command to install them repectively could increase the cache hit.