Add MACSec show & config CLIs multi-namespace support

[shyam77git]

[ June/10] Per Junhua/Judy: The config/show macsec commands are not yet enhanced for multi-asic, it needs to support the namespace parameter.

[ June/10] Shyam's update : As we discussed in last sync-up, MACSec show and config CLIs are not blocking for POC-2 However, in order to make progress on them for upcoming milestones (staging/pilot etc.) and assess where they stand from end-to-end validation etc. standpoint, MSFT-CSCO planned to work on it.

Also, any fix/enhancement in MACSec should consider multi-ASIC/NPU SONiC architecture, workflow. CLI/ workflow validation can only happen with multi-ASIC and not on single-ASIC as ‘-n ’ input is mandatory. For instance, this case, config via MACSec config CLI goes to config_db and not to be required config_db<X> file. X for the right NPU in multi-NPU environment.

[June/24] Junhua: We are looking into its fix. Please raise a github issue.

[shyam77git]

@jimmyzhai : Filed this git issue per the discussion