* makes rlnlib target optional
* makes the rln-related targets conditioned to the RLN command line flag
* adds the rln compiler flag condition
* adds the rln compiler flag condition to the rln module
* wakunode2 rln conditional compilation
* updates wakunode2 test
* updates waku rln relay tests
* removing the rln test from the default imports of the v2 tests
* imports rln module conditionally
* removes the rln flag condition from the rln module
* separates rln data types from its procs
* adds the import statement
* brings back the contract def to the rln utils
* adds rln module import to the rln unit tests
* clean up and reorganization
* adds a todo
* minor edits on a comment
Sanaz Taheri Boshrooyeh