Upgrade, cleanup and improve

[dimitris-norce]

• Upgraded to .NET 4.8
• Upgraded all nugets to their latest versions
• Removed binding redirects
• Removed unused references
• Migrated packages.config to PackageReferences
• Fixed possible Null Reference exception, when loading appsettings
• Slightly improved logging for the above scenario
• Added option to Copy more collections, after the operation is finished. This allows the user to return to the first page, without having to close and re-open the tool. Useful if you need to run the operation on multiple collections/DBs.

[dimitris-norce]

@microsoft-github-policy-service agree