[xcvrd] Optimize module initialization performance (#611)

[Junchao-Mellanox]

Backport PR sonic-net/sonic-platform-daemons#611

Description

1. Use hget instead of hgetall to gain better performance
2. Optimize SfpStateUpdateTask.init:

• Use cache in this function for different logical ports with the same physical module.
• Handles transceiver info table and media settings before any other table.

Motivation and Context

Improve module initialization performance. Due my test:

1. hget is 7 times faster than hgetall when getting cmis module state
2. Before optimizing SfpStateUpdateTask.init, the last module takes about 5 minutes to finish notify_media_settings call; after the optimization, the last module takes about 1 minutes to finish notify_media_settings` call.

How Has This Been Tested?

Manual test

Additional Information (Optional)