chore: create automated build & publish process on github actions

[mhordynski]

CoS: we have a single trigger to run build / packaging process & publishing packages to pypi registry

Glossary:

• ragbits - aggregation package which downloads all common packages to quickstart new user
• ragbits-core - core function & common utilities used by other packages
• ragbits-sample-module - an example of a module which is self-contained and can require only ragbits-core as dependency (for example ragbits-document-search)

We have following scenarios:

• updating ragbits-sample-module:

  • version bump on ragbits-sample-module
  • make a change in ragbits dependencies
  • version bump on ragbits aggregation package

• updating ragbits-core:

  • version bump on ragbits-core
  • make a change in ALL ragbits-sample-module-like packages (update core dependency)
  • version bump on ALL ragbits-sample-module-like packages
  • make a change in ragbits dependencies
  • version bump on ragbits aggregation package