[xcvrd] Enable periodic polling of VDM relevant data

[mihirpat1]

Description

VDM data from xcvrd needs to be read and the redis-db needs to be updated accordingly.

Motivation and Context

VDM data from xcvrd needs to be read in the following manner so that the data can be accessed through CLI as well as Streaming telemetry dynamically.

1. VDM threshold values should be read during transceiver detection. We don't need to poll this data periodically since the threshold values are static
2. VDM real/sample values and VDM flag values should be read periodically by the DomInfoUpdateTask thread

The table and field related details for the above fields can be found in HLD for diagnostic monitoring of CMIS based transceivers by mihirpat1 · Pull Request #1828 · sonic-net/SONiC

Freeze/Unfreeze of VDM data
Also, VDM statistics are frozen before reading VDM real values, VDM flag values and PM values and are unfrozen after the read operation is completed.

VDM metadata update for VDM flags
All the VDM metadata fields for VDM flags are now being updated. This includes updated the flag change count, last set and last clear time as part of periodic polling by the DomInfoUpdateTask thread.
The change counters and set/clear time tables will be present for only 1 subport for a port breakout group. This has been done inline to future direction wherein the dignostic tables will be maintained only for first subport and not for other subports of the port breakout group.

Other related changes in this PR

1. Skip reading all diagnostic info if transceiver is not present on a port. This is now done at the beginning of the diagnostic polling loop to optimize the polling routine
2. Read VDM and PM data only if VDM is supported on a transceiver
3. The del_port_sfp_dom_info_from_db function has now been modified to make it more generic and to reduce modifying the implementation while adding new tables in future
4. Moved xcvrd/dom_mgr.py to xcvrd/dom/dom_mgr.py
5. Modified a warning to debug in handle_port_update_event to reduce flooding of logs

How Has This Been Tested?

Modules tested

1. CMIS module
2. C-CMIS module
3. SFF-8472 module

Test cases attempted

1. Dumped VDM threshold value tables
2. Dumped VDM real value tables
3. Dumped VDM flag value tables
4. Dumped VDM metadata tables
5. Ensure all VDM related tables are empty after xcvrd stop

Additional Information (Optional)

This PR needs to be merged only after the below PR is merged.
sonic-net/sonic-platform-common#527

MSFT ADO - 30598749

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[prgeor]

@mihirpat1 can you make this log as debug log?
https://github.com/sonic-net/sonic-platform-daemons/blob/master/sonic-xcvrd/xcvrd/xcvrd_utilities/port_event_helper.py#L147

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mihirpat1]

@mihirpat1 can you make this log as debug log? https://github.com/sonic-net/sonic-platform-daemons/blob/master/sonic-xcvrd/xcvrd/xcvrd_utilities/port_event_helper.py#L147

@prgeor I have addressed this now.