Metanorma package or release commands

[ronaldtse]

In the real world Metanorma documents are often 'published' or 'packaged' for submission or for archival for certain stage.

For example, the ISO 8601-1 Amendment document needed to be submitted to ISO/CS for DAmd stage ballot.

What I did was to make a git release tag (e.g. by date and stage 20201208-damd). In the release package, I zipped up the documents/ directory to contain the full mini-site and all MN generated artifacts with the build log (*.err).

This occurred to me that it is similar to the rake release process where the gem is built, packaged, then pushed to rubygems.org. In the near future we will have the MN document registry, which can accept published packages.

Therefore we should have a metanorma package command that builds and packages MN documents (or a collection of documents).

This issue is to specify out behavior of the command metanorma package and metanorma release (which includes the push).