* chore: fix Makefile pre-build
* chore: add Makefile command to install depenedncy cargo-make
* chore: update all READMEs with instructions to install dependencies, build and test
* chore: add target to fetch all submodules
* feat(rln): expand documentation with minimal public API usage example
* refactor(rln): ease RLN interaction with new APIs
* feat(rln): expand API docs
* fix(rln): disable doctest for rln