Publish on Mops

[ZenVoich]

Related issue #617

Adds ability to publish a package to the mops registry when a production github release is created.

What changed:

• Updated ic-mops to 0.39.2
• Updated readme
• Changed imports in tests to relative paths, because a package with local dependencies cannot be published on mops.
• Added CHANGELOG.md with example text for the version 0.10.3
• Added [package] section to mops.toml
• Added [toolchain] section to mops.toml, which specifies the versions of moc and wasmtime that will be used to run tests.
• Added mops-publish.yml github action

To publish:

• Add MOPS_IDENTITY_PEM to github secrets (one-time)
• Bump version in mops.toml
• Make sure there is a paragraph with that version in CHANGELOG.md (e.g. ## 0.10.3 or ## 0.10.4 (2024-01-10)
• Create a production GitHub Release

On publish:

• Mops will run tests, and if the tests fail, the publication will be aborted
• Documentation is generated automatically

[crusso]

Ah, one question though. I don't think base actually publishes releases per se. We just a git tag every time we release moc. Will that be an issue? @ggreif whaddya think?

UPDATE: I guess its just a matter of pushing a button, or adding a GH action that watches for certain tags to push a release - something similar to what we do on the moc repo.

[crusso]

@rvanasa I'll let you push the merge button when you are ready (obviously not over the weekend)

[rvanasa]

As a quick update, we are ready to merge after configuring the GitHub secret (waiting on an internal IT process). @ZenVoich, thanks again for preparing this PR!

[rvanasa]

The GH secret is now configured! @ZenVoich, here is a PR to fix the merge conflicts: https://github.com/ZenVoich/motoko-base/pull/2