MEP 21 -- Support compile and run on Mac

Current state: Under Discussion

ISSUE: https://github.com/milvus-io/milvus/issues/12777

PRs: 

Keywords: Restful API

Released:

Summary(required)

Separating knowhere from Milvus project make Milvus easy to run on Mac or other laptops, due to decoupling knowhere that is the engine module make code structure more clear. 

Motivation(required)

Compiling and running Milvus on Mac is a common requirement, which is helpful for work on the Mac laptop.

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Design Details(required)

Test Plan(required)

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