Multiple current deploy linking strategies

[edudobay]

In some use cases it might be necessary or desired that the realpath for the deployment directory stays the same.

For example, the Rollbar tracker expands the path when grouping exceptions and hence an exception might be tracked as separate issues across deploys because the file paths on the stack traces have changed.

Regarding the Rollbar tracker, we could also investigate whether it has an option to normalize the base path so that we could solve this issue there.