version >= 0.3.18, < 0.4 map functionality only works with server/worker architecturee

[xgui3783]

From siibra-api version >= 0.3.18, <0.4, all endpoints map/* will only work in a server/worker architecture. Additionally, the worker's build pipeline (requiring siibra-python v2.0) is slightly different (see worker-v4.dockerfile ).

This is to address the memory usage issue of previous versions of siibra-api (< 0.3.18, siibra-python v0.4) in map endpoints, where point assignment becomes unreliable.

This situation is expected to be resolved by 0.4.0, where all worker nodes will require siibra-python 2.0