[System.Data] referencesource -> corefx (#4299)
* [System.Data] SQLTypes from corefx
* [System.Data] DataStorage + subclasses from corefx
* [System.Data] remove dead referencesource.sources references
* [System.Data] Generate SR.cs from corefx using resx2sr tool
* [System.Data] move common references to corefx.common.sources
* [System.Data] remove /ReferenceSources/SR.cs
* [System.Data] remove duplicates in corefx.common.sources (accidentally were added)
* [System.Data] simple types & enums from corefx
* [System.Data] referencesource -> corefx
* [System.Data] Referencesource -> corefx
* [System.Data] re-order (sort) files in corefx.common.sources, DbCommandBuilder from corefx
* [System.Data] Referencesource -> corefx
* [System.Data] DataRow, DataSet, Filters, etc from corefx. XmlDataDocument is internal in corefx but used to be public in mono.
* [System.Data] rollback referencesource changes
* [System.Data] Wrap /referencesource/DataSet.cs with #ifdef COREFX in order to include missing DataSetSchemaImporterExtension and ignore DataSet