Create advanced pack task

[gep13]

Advanced task where one could specify most common meta data right in the task without need for nuspec.

Most of our files/file are just something like <file src="src\SqlBulkSync\SqlBulkSync\bin\Release\**" target="tools" />

so if one could config source files something like this in UI

src\SqlBulkSync\SqlBulkSync\bin\$(BuildConfiguration)\**

and you could use all the pipeline variables to get it right