.NET emitter should output brand-new package scaffolding (CHANGELOG, README, tests, samples)

[m-redding]

CHANGELOG scaffolding is needed in the azsdkcli as described in Azure/azure-sdk-tools#14791

samples scaffolding is needed in the azsdkcli as described in Azure/azure-sdk-tools#14787 - Currently .NET is the only language that doesn't do this

Also would be nice to close the other gaps as described in Azure/azure-sdk-tools#14029 (comment) namely: tests and README