HLD for Redis Client Manager

[ayelrod]

This HLD describes a design for using Redis connection pools in sonic-mgmt-common to reduce stress on the Redis Unix/TCP socket.

[linux-foundation-easycla[bot]]

The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: ayelrod / name: Lucas Rodriguez (0e008d012b70153dd761ed694e9c50feb12b3e67, 0afb5e8771640ecda2db901b8505fce04759f9f8, 9135500ad1ec26d18686a1de31e1bbab3830af83)

[ayelrod]

Hi @sachinholla , can you please approve the PR if there are no more comments? Thanks!