Support publishing packages

[jechol]

hamler build outputs only .ebin files.

Intermediary .erl files are necessary to publish it as a package to hex.pm.

[slashmili]

The hamler libraries should push .hm files to hex so other hamler projects can get the benefit of using typed data structure.

I know for the fact that Gleam is pushing .gleam files to hexpm. e.g: https://hex.pm/packages/gleam_crypto