Add option to symlink from remote dir in packager

[hemildesai]

Example usage of interface:

reuse_dir = exp.tunnels[ssh_tunnel.key].packaging_jobs["my-test-run"].dst_path
if reuse_dir:
     executor.packager.symlink_from_remote_dir = reuse_dir

Interface can be changed if needed.

[Kipok]

Thanks, works great!

[Kipok]

Would be nice to do the same for local runs as well. But not as important as current changes, so we can keep it in the backlog

[hemildesai]

Created #126