deploy: Symlink instead of copy local.py

This way you can edit all your configs in /etc/socorro
deploy: Clean up, an allow editing of config.

This puts some paths in a variable to make it cleaner, and prompts the user to
edit /etc/socorro files before continuing.
Merge pull request #2115 from jorgenpt/deploy-symlink-local-py

deploy: Symlink instead of copy local.py