Common error variables

Currently we have code similar to the following sprinkled throughout the project

return errors.New("foo-not-found")

or

return fmt.Errorf("some error: %s", err)

This really should be cleaned up so that we define some common errors that are used throughout the code, i.e

var ErrNotFound = errors.New("not-found")

as well as we should start using error wrapping

return fmt.Errorf("some context: %w")

errors.Is()

with respect to common errors, there is an assumption that a common "not-found" is just as good as a specific "foo-not-found" as the code that logs the error should (a) be determining what needs to be logged and (b) the unwrapping should give the appropriate context.