Support multiple instances of same connector

Description

Support for multiple credentialed instances of the same connector, so 2 instances of a connector can be used on a site. Initial implementation is a code-only solution with no UI.

Note: After upgrading the MAI package, the form may display 2 dropdown lists for selecting the mapping.
This occurs because, after the new connector updates the name of the .dll file around the MAI framework and you publish the site to another location (such as to the cloud or an IIS site), the old .dll file is not automatically deleted.

To remove the old.dll:

1. Go to the Publish dialog.
2. Click the Settings tab.
3. Under File Publish Options, check Remove additional files at destination.