compile-releases: Configure merging behavior

[jpmckinney]

See docs: https://ocds-merge.readthedocs.io/en/latest/handle-bad-data.html

The user should be able to add options for how the compile-releases step behaves. (see #222)

[jpmckinney]

I documented how to approach this in #222 (comment)

Not a priority as we currently know no publishers requiring custom merge rules (Contracts Finder fixed their issue).