figure out what to do for package managers that do not execute post-link/post-install scripts

It turns out that in the standardization process for conda, the following scripts were made optional:

- pre-link: Executed before a package is installed / linked.
- post-link: Executed after a package is installed / linked.
- pre-unlink: Executed before a package is removed / unlinked.
- post-unlink: Executed after a package is removed / unlinked. Deprecated; MAY be ignored.

This is a breaking change and not all package managers handle these scripts.

We had relied on them in conda-forge and so now we need to go back and clean them up.

This means that some older packages will now be broken.