Contributor guide: How to develop and publish a module

[Totktonada]

• A module template (modulekit: luakit / ckit).
• Lua/C style guides.
• How to handle third-party dependencies.
• How to setup CI / CD.
  • How to setup testing.
  • Publish rockspec.
  • Publish RPM / Deb package.
  • Publish documentation.
  • Publish a docker image.

• How to publish the module on our GitHub and website.
  • Don't forget about our side steps: fork the repo, add credentials to CI variables, trigger first build, etc.

Part of umbrella issue #1444.

In fact this issue requires to work on the template and infrastructure. I'll file relevant issues to the modulekit repository later.

NB: Don't forget about the following tasks:

• Provide an exaple how to implement pure Lua/C module without Lua wrapper. Show how to load a Lua file from such module (build it into the dynamic library).
• Implement and setup deployment service for RPM / Deb like one we have for luarocks.
• Consider GitHub Actions as CI, which supports automatic genetation of a job list. It is useful for eliminate need to manually update a list of supported Linux distros (for which packages are building and deploying) and supported tarantool versions (on which tests are run).

[Totktonada]

There are signs of the old war around storing rockspecs: whether it should be rockspecs/ directory with scm-1 and all releases or just scm-1 in the root of the project. All past discussions are gone, the only thing I found is @rosik's chat question: whether there is any reason to store all release rockspecs in the repository.

I would summon @Mons and @orchaton into the discussion.