ADF cmdlets better Piping support and removing dependencies on credentials in mock test recording

Two changes in this PR:

1. Better piping support in ADF Cmdlets by adding Alias for each -Name parameter:
    Our wrapper classes usually have properties like LinkedServiceName, PipelineName, HubName, etc.
    When user does a Get-AzureDataFactoryLinkedService ... | Remove-AzureDataFactoryService, the -Name required by the Remove cmdlet is missing.  So this change will add LinkedServiceName as the Alias of Name so that the Piping experience is better supported while not breaking the existing -Name contract with the user (and we still encourage users to use -Name)

    I've added mock tests for each affected scenarios, i.e. DataFactory, LinkedService, Table, Pipeline, and Hub.  Gateway is not affected so I leave it alone.

2.  Removed any JSON which requires real credentials while running in Mock test recording mode.
    Our previous session records are recorded with real credentials and the search and replaced with non-confidential strings.  This becomes extremely inconvenient now and hence I created the new JSONs don't require any real credentials to have the recording test run against our live site.