The taskhash package imports the graph package to use this type. In a
future commit, I need to make the graph package also import the taskhash
package. This will cause an import cycle. Pulling this struct out into
its own package will take me one step closer to being able to remove the
graph import from the taskhash package.

I had to also rename the struct from WorkspaceInfos to something else (I
chose Catalog), because golangci-lint warns (which fails our CI) that
workspace.WorkspaceInfo can be an "annoying" name.

This is an aesthetic change. I was having trouble reading a reference to
this struct and package with different names everywhere, so I'm renaming
it all to the same name.

This finishes the swing for removing the graph import in the taskhash
package. As mentioned in b7324b6, this will allow me to do the
inverse: to import the taskhash package into the graph package.

Give the CompleteGraph struct access to the TaskHashTracker instance
so we can use it while constructing PackageTasks. PackageTasks are
then available when walking the graph during dry run execution, and
we can add them into the Dry Run output. This approach also makes it
trivial to use the PackageTask.ExpandedInputs during RealRun execution
so we can print them as debug output in a Run Summary

…ch-task-summary

…ace)

…skhash package