feat(rln-wasm-utils): extracting identity generation and hash functions into a separate module (#332)

- separated all identity generation functions as separate functions,
rather than RLN methods
- added BE support - only for these functions so far
- covered the functions with tests, as well as conversion to big endian
- prepared for publication, but is actually awaiting the initial
publication of the RLN module

@vinhtc27, please check that everything is correct from the wasm point
of view. This module does not require parallel computing, so if there
are any unnecessary dependencies, builds, etc., please let me know.

---------

Co-authored-by: vinhtc27 <vinhtc27@gmail.com>

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 members = ["rln", "rln-cli", "utils"]
-exclude = ["rln-wasm"]
+exclude = ["rln-wasm", "rln-wasm-utils"]
 resolver = "2"
 
 # Compilation profile for any non-workspace member.