Add support for multithreading and CSV data migration engine features

[ksulikow]

Data migration engine has built in support for multithreading and CSV fields format, but it is not supported by package deployer. It can be easy implemented by adding additional config parameters and using data engine features.

[tdashworth]

As an example, we can use what @ksulikow has added to the samples project for the migrator itself.

https://github.com/Capgemini/xrm-datamigration/commit/ba8ac3554084bb266ecba5673fa097c5317d4e28

[tdashworth]

For configuration, I think we can add two optional parameters for type and threads count:

<templateconfig>
    <dataimports>
        <dataimport 
            datafolderpath="ConfigurationData/Extract"
            importconfigpath="ConfigurationData/ImportConfig.json"
            importbeforesolutions="true"
            type="json"
            threadcount="4"/>
    </dataimports>
</templateconfig>

The type property should default to json although if blank a warning message should be displayed stating:

Assuming JSON as data type for import. Please specify a type for this import using type="json" to prevent this message.

The threadcount property should default to 1 and no message needs to be shown.

[tdashworth]

@ksulikow @ewingjm please take a look at my above comment and share any thoughts you might have. 😄