VTAdmin: Enhance VReplication functionality in vtadmin UI

[rohit-nayak-ps]

Feature Description

This is an umbrella issue for adding more support for VReplication Workflows in VTAdmin.

Use Case(s)

Here are some initial features we will plan to add to vtadmin-related to vrep workflows. These can be implemented in any order.

• Display workflow type/subtype in current page which displays workflows in a keyspace https://github.com/vitessio/vitess/pull/11685

• Improved display of workflow details https://github.com/vitessio/vitess/issues/16537

• Stop/start existing workflow #16675

• Running VDiff on existing workflows #16943

• Creating a new MoveTables workflow #16707

• All actions on existing workflows including switching and reversing traffic, canceling/completing #16816

• Creating a new Reshard workflow #16903

• Creating a new Materialize workflow #16941

• Modifying existing workflows for updating limited attributes, (which will not invalidate the workflow ...)

• Improved error detection and suggesting resolutions for standard errors

• Display important metrics in a user-friendly way